256643626 has 8 divisors (see below), whose sum is σ = 388777284. Its totient is φ = 127051200.

The previous prime is 256643617. The next prime is 256643627. The reversal of 256643626 is 626346652.

It can be written as a sum of positive squares in 2 ways, for example, as 197430601 + 59213025 = 14051^2 + 7695^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (256643627) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 635055 + ... + 635458.

Almost surely, 2^256643626 is an apocalyptic number.

256643626 is a deficient number, since it is larger than the sum of its proper divisors (132133658).

256643626 is a wasteful number, since it uses less digits than its factorization.

256643626 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1270616.

The product of its digits is 311040, while the sum is 40.

The square root of 256643626 is about 16020.1006863253. The cubic root of 256643626 is about 635.4921070108.

The spelling of 256643626 in words is "two hundred fifty-six million, six hundred forty-three thousand, six hundred twenty-six".