644332004 has 6 divisors (see below), whose sum is σ = 1127581014. Its totient is φ = 322166000.

The previous prime is 644331967. The next prime is 644332019. The reversal of 644332004 is 400233446.

It can be written as a sum of positive squares in only one way, i.e., 595360000 + 48972004 = 24400^2 + 6998^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80541497 + ... + 80541504.

It is an arithmetic number, because the mean of its divisors is an integer number (187930169).

Almost surely, 2^644332004 is an apocalyptic number.

It is an amenable number.

644332004 is a deficient number, since it is larger than the sum of its proper divisors (483249010).

644332004 is a wasteful number, since it uses less digits than its factorization.

644332004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161083005 (or 161083003 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 26.

The square root of 644332004 is about 25383.6956332209. The cubic root of 644332004 is about 863.7138845294.

The spelling of 644332004 in words is "six hundred forty-four million, three hundred thirty-two thousand, four".