645554644 has 24 divisors (see below), whose sum is σ = 1291792320. Its totient is φ = 276519936.

The previous prime is 645554603. The next prime is 645554669. The reversal of 645554644 is 446455546.

645554644 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 645554644.

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, 60564 + ... + 70420.

It is an arithmetic number, because the mean of its divisors is an integer number (53824680).

Almost surely, 2^645554644 is an apocalyptic number.

It is an amenable number.

645554644 is an abundant number, since it is smaller than the sum of its proper divisors (646237676).

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

645554644 is a wasteful number, since it uses less digits than its factorization.

645554644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12207 (or 12205 counting only the distinct ones).

The product of its digits is 1152000, while the sum is 43.

The square root of 645554644 is about 25407.7673950310. The cubic root of 645554644 is about 864.2598473263.

The spelling of 645554644 in words is "six hundred forty-five million, five hundred fifty-four thousand, six hundred forty-four".