644297792 has 28 divisors (see below), whose sum is σ = 1293943056. Its totient is φ = 318264960.

The previous prime is 644297783. The next prime is 644297833. The reversal of 644297792 is 297792446.

It is a self number, because there is not a number n which added to its sum of digits gives 644297792.

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, 55334 + ... + 65957.

It is an arithmetic number, because the mean of its divisors is an integer number (46212252).

Almost surely, 2^644297792 is an apocalyptic number.

It is an amenable number.

644297792 is an abundant number, since it is smaller than the sum of its proper divisors (649645264).

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

644297792 is a wasteful number, since it uses less digits than its factorization.

644297792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121386 (or 121376 counting only the distinct ones).

The product of its digits is 1524096, while the sum is 50.

The square root of 644297792 is about 25383.0217271309. The cubic root of 644297792 is about 863.6985974299.

The spelling of 644297792 in words is "six hundred forty-four million, two hundred ninety-seven thousand, seven hundred ninety-two".