256515864 has 32 divisors (see below), whose sum is σ = 699589440. Its totient is φ = 77732000.

The previous prime is 256515851. The next prime is 256515869. The reversal of 256515864 is 468515652.

256515864 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256515869) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 485562 + ... + 486089.

It is an arithmetic number, because the mean of its divisors is an integer number (21862170).

Almost surely, 2^256515864 is an apocalyptic number.

256515864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

256515864 is an abundant number, since it is smaller than the sum of its proper divisors (443073576).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256515864 is a wasteful number, since it uses less digits than its factorization.

256515864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 971671 (or 971667 counting only the distinct ones).

The product of its digits is 288000, while the sum is 42.

The square root of 256515864 is about 16016.1126369666. The cubic root of 256515864 is about 635.3866362191.

The spelling of 256515864 in words is "two hundred fifty-six million, five hundred fifteen thousand, eight hundred sixty-four".