644485280 has 48 divisors (see below), whose sum is σ = 1524114144. Its totient is φ = 257537280.

The previous prime is 644485279. The next prime is 644485297. The reversal of 644485280 is 82584446.

644485280 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×644485280² = 830722552273356800, which contains 22 as substring.

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, 319475 + ... + 321485.

It is an arithmetic number, because the mean of its divisors is an integer number (31752378).

Almost surely, 2^644485280 is an apocalyptic number.

It is an amenable number.

644485280 is an abundant number, since it is smaller than the sum of its proper divisors (879628864).

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

644485280 is a wasteful number, since it uses less digits than its factorization.

644485280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4029 (or 4021 counting only the distinct ones).

The product of its (nonzero) digits is 245760, while the sum is 41.

The square root of 644485280 is about 25386.7146358090. The cubic root of 644485280 is about 863.7823668813.

The spelling of 644485280 in words is "six hundred forty-four million, four hundred eighty-five thousand, two hundred eighty".