644737480 has 32 divisors (see below), whose sum is σ = 1451483640. Its totient is φ = 257748480.

The previous prime is 644737447. The next prime is 644737517. The reversal of 644737480 is 84737446.

It can be written as a sum of positive squares in 4 ways, for example, as 469068964 + 175668516 = 21658^2 + 13254^2 .

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, 91690 + ... + 98470.

Almost surely, 2^644737480 is an apocalyptic number.

It is an amenable number.

644737480 is an abundant number, since it is smaller than the sum of its proper divisors (806746160).

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

644737480 is a wasteful number, since it uses less digits than its factorization.

644737480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9169 (or 9165 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 43.

The square root of 644737480 is about 25391.6813149504. The cubic root of 644737480 is about 863.8950239686.

The spelling of 644737480 in words is "six hundred forty-four million, seven hundred thirty-seven thousand, four hundred eighty".