256691264 has 14 divisors (see below), whose sum is σ = 509371854. Its totient is φ = 128345600.

The previous prime is 256691261. The next prime is 256691291. The reversal of 256691264 is 462196652.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 207129664 + 49561600 = 14392^2 + 7040^2 .

It is not an unprimeable number, because it can be changed into a prime (256691261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2005337 + ... + 2005464.

Almost surely, 2^256691264 is an apocalyptic number.

It is an amenable number.

256691264 is a deficient number, since it is larger than the sum of its proper divisors (252680590).

256691264 is an equidigital number, since it uses as much as digits as its factorization.

256691264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4010813 (or 4010803 counting only the distinct ones).

The product of its digits is 155520, while the sum is 41.

The square root of 256691264 is about 16021.5874369552. The cubic root of 256691264 is about 635.5314244365.

The spelling of 256691264 in words is "two hundred fifty-six million, six hundred ninety-one thousand, two hundred sixty-four".