256643632 has 40 divisors (see below), whose sum is σ = 572788736. Its totient is φ = 109118016.

The previous prime is 256643627. The next prime is 256643669. The reversal of 256643632 is 236346652.

It is a junction number, because it is equal to n+sod(n) for n = 256643591 and 256643600.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5203 + ... + 23245.

Almost surely, 2^256643632 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 256643632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (286394368).

256643632 is an abundant number, since it is smaller than the sum of its proper divisors (316145104).

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

256643632 is a wasteful number, since it uses less digits than its factorization.

256643632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18185 (or 18179 counting only the distinct ones).

The product of its digits is 155520, while the sum is 37.

The square root of 256643632 is about 16020.1008735900. The cubic root of 256643632 is about 635.4921119631.

The spelling of 256643632 in words is "two hundred fifty-six million, six hundred forty-three thousand, six hundred thirty-two".