643421126256 has 40 divisors (see below), whose sum is σ = 1662239343504. Its totient is φ = 214464921600.

The previous prime is 643421126221. The next prime is 643421126269. The reversal of 643421126256 is 652621124346.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 967050 + ... + 1490646.

Almost surely, 2^643421126256 is an apocalyptic number.

It is an amenable number.

643421126256 is an abundant number, since it is smaller than the sum of its proper divisors (1018818217248).

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

643421126256 is a wasteful number, since it uses less digits than its factorization.

643421126256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 549209 (or 549203 counting only the distinct ones).

The product of its digits is 414720, while the sum is 42.

The spelling of 643421126256 in words is "six hundred forty-three billion, four hundred twenty-one million, one hundred twenty-six thousand, two hundred fifty-six".