511 has 4 divisors (see below), whose sum is σ = 592. Its totient is φ = 432.

The previous prime is 509. The next prime is 521. The reversal of 511 is 115.

511 is nontrivially palindromic in base 2 and base 8.

It is a Cunningham number, because it is equal to 2^{9}-1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 115 = 5 ⋅23.

It is a 4-Lehmer number, since φ(511) divides (511-1)^{4}.

It is a cyclic number.

It is not a de Polignac number, because 511 - 2^{1} = 509 is a prime.

It is a super-2 number, since 2×511^{2} = 522242, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (7), and also a Moran number because the ratio is a prime number: 73 = 511 / (5 + 1 + 1).

It is a Duffinian number.

511 is a modest number, since divided by 11 gives 5 as remainder.

511 is a lucky number.

511 is a nontrivial repdigit in base 2 and base 8.

It is a plaindrome in base 2, base 4, base 8, base 12 and base 16.

It is a nialpdrome in base 2, base 6, base 8 and base 10.

It is a zygodrome in base 2, base 6 and base 8.

It is a junction number, because it is equal to *n*+sod(*n*) for *n* = 494 and 503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521) by changing a digit.

It is a nontrivial repunit in base 2.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30 + ... + 43.

It is an arithmetic number, because the mean of its divisors is an integer number (148).

511 is a deficient number, since it is larger than the sum of its proper divisors (81).

511 is an equidigital number, since it uses as much as digits as its factorization.

511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80.

The product of its digits is 5, while the sum is 7.

The square root of 511 is about 22.6053091109. The cubic root of 511 is about 7.9947882721.

Adding to 511 its reverse (115), we get a palindrome (626).

It can be divided in two parts, 5 and 11, that multiplied together give a palindrome (55).

The spelling of 511 in words is "five hundred eleven", and thus it is an aban number and an oban number.

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