256620643 has 8 divisors (see below), whose sum is σ = 258428016. Its totient is φ = 254820000.

The previous prime is 256620629. The next prime is 256620709. The reversal of 256620643 is 346026652.

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

It is a cyclic number.

It is not a de Polignac number, because 256620643 - 2²¹ = 254523491 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 256620599 and 256620608.

It is not an unprimeable number, because it can be changed into a prime (256620613) 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, 92253 + ... + 94993.

It is an arithmetic number, because the mean of its divisors is an integer number (32303502).

Almost surely, 2^256620643 is an apocalyptic number.

256620643 is a deficient number, since it is larger than the sum of its proper divisors (1807373).

256620643 is a wasteful number, since it uses less digits than its factorization.

256620643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3365.

The product of its (nonzero) digits is 51840, while the sum is 34.

The square root of 256620643 is about 16019.3833526762. The cubic root of 256620643 is about 635.4731365402.

The spelling of 256620643 in words is "two hundred fifty-six million, six hundred twenty thousand, six hundred forty-three".