644485800 has 96 divisors (see below), whose sum is σ = 2283336000. Its totient is φ = 147310080.

The previous prime is 644485789. The next prime is 644485813. The reversal of 644485800 is 8584446.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 72525 + ... + 80924.

It is an arithmetic number, because the mean of its divisors is an integer number (23784750).

Almost surely, 2^644485800 is an apocalyptic number.

644485800 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

644485800 is an abundant number, since it is smaller than the sum of its proper divisors (1638850200).

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

644485800 is a wasteful number, since it uses less digits than its factorization.

644485800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153475 (or 153466 counting only the distinct ones).

The product of its (nonzero) digits is 122880, while the sum is 39.

The square root of 644485800 is about 25386.7248773842. The cubic root of 644485800 is about 863.7825991942.

The spelling of 644485800 in words is "six hundred forty-four million, four hundred eighty-five thousand, eight hundred".