256638976 has 76 divisors (see below), whose sum is σ = 566229960. Its totient is φ = 115343360.

The previous prime is 256638973. The next prime is 256638979. The reversal of 256638976 is 679836652.

It is an interprime number because it is at equal distance from previous prime (256638973) and next prime (256638979).

It is not an unprimeable number, because it can be changed into a prime (256638973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2883540 + ... + 2883628.

Almost surely, 2^256638976 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256638976, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (283114980).

256638976 is an abundant number, since it is smaller than the sum of its proper divisors (309590984).

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

256638976 is an frugal number, since it uses more digits than its factorization.

256638976 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136 (or 102 counting only the distinct ones).

The product of its digits is 3265920, while the sum is 52.

The square root of 256638976 is about 16019.9555554939. The cubic root of 256638976 is about 635.4882689310.

The spelling of 256638976 in words is "two hundred fifty-six million, six hundred thirty-eight thousand, nine hundred seventy-six".