644034620 has 24 divisors (see below), whose sum is σ = 1361556000. Its totient is φ = 255883712.

The previous prime is 644034557. The next prime is 644034673. The reversal of 644034620 is 26430446.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 105080 + ... + 111039.

It is an arithmetic number, because the mean of its divisors is an integer number (56731500).

Almost surely, 2^644034620 is an apocalyptic number.

It is an amenable number.

644034620 is an abundant number, since it is smaller than the sum of its proper divisors (717521380).

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

644034620 is a wasteful number, since it uses less digits than its factorization.

644034620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216277 (or 216275 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 29.

The square root of 644034620 is about 25377.8371812887. The cubic root of 644034620 is about 863.5809850229.

The spelling of 644034620 in words is "six hundred forty-four million, thirty-four thousand, six hundred twenty".