264517681 has 2 divisors, whose sum is σ = 264517682. Its totient is φ = 264517680.

The previous prime is 264517679. The next prime is 264517741. The reversal of 264517681 is 186715462.

264517681 = T₁₃₂₇₈ + T₁₃₂₇₉ + T₁₃₂₈₀.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 216090000 + 48427681 = 14700^2 + 6959^2 .

It is a cyclic number.

It is not a de Polignac number, because 264517681 - 2¹ = 264517679 is a prime.

It is a super-2 number, since 2×264517681² = 139939207123235522, which contains 22 as substring.

Together with 264517679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (264517621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 132258840 + 132258841.

It is an arithmetic number, because the mean of its divisors is an integer number (132258841).

Almost surely, 2^264517681 is an apocalyptic number.

264517681 is the 13280-th centered triangular number.

It is an amenable number.

264517681 is a deficient number, since it is larger than the sum of its proper divisors (1).

264517681 is an equidigital number, since it uses as much as digits as its factorization.

264517681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80640, while the sum is 40.

The square root of 264517681 is about 16263.9995388588. Note that the first 3 decimals coincide. The cubic root of 264517681 is about 641.9259052437.

The spelling of 264517681 in words is "two hundred sixty-four million, five hundred seventeen thousand, six hundred eighty-one".