644216992 has 24 divisors (see below), whose sum is σ = 1269021600. Its totient is φ = 321925824.

The previous prime is 644216987. The next prime is 644217011. The reversal of 644216992 is 299612446.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65109 + ... + 74347.

It is an arithmetic number, because the mean of its divisors is an integer number (52875900).

Almost surely, 2^644216992 is an apocalyptic number.

It is an amenable number.

644216992 is a deficient number, since it is larger than the sum of its proper divisors (624804608).

644216992 is a wasteful number, since it uses less digits than its factorization.

644216992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11428 (or 11420 counting only the distinct ones).

The product of its digits is 186624, while the sum is 43.

The square root of 644216992 is about 25381.4300621537. The cubic root of 644216992 is about 863.6624910595.

The spelling of 644216992 in words is "six hundred forty-four million, two hundred sixteen thousand, nine hundred ninety-two".