644945272 has 24 divisors (see below), whose sum is σ = 1276273800. Its totient is φ = 305499024.

The previous prime is 644945267. The next prime is 644945321. The reversal of 644945272 is 272549446.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 108772 + ... + 114547.

It is an arithmetic number, because the mean of its divisors is an integer number (53178075).

Almost surely, 2^644945272 is an apocalyptic number.

It is an amenable number.

644945272 is a deficient number, since it is larger than the sum of its proper divisors (631328528).

644945272 is a wasteful number, since it uses less digits than its factorization.

644945272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223363 (or 223340 counting only the distinct ones).

The product of its digits is 483840, while the sum is 43.

The square root of 644945272 is about 25395.7727190964. The cubic root of 644945272 is about 863.9878220449.

The spelling of 644945272 in words is "six hundred forty-four million, nine hundred forty-five thousand, two hundred seventy-two".