644462144 has 14 divisors (see below), whose sum is σ = 1278854694. Its totient is φ = 322231040.

The previous prime is 644462089. The next prime is 644462207. The reversal of 644462144 is 441264446.

It can be written as a sum of positive squares in only one way, i.e., 629407744 + 15054400 = 25088^2 + 3880^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5034797 + ... + 5034924.

Almost surely, 2^644462144 is an apocalyptic number.

644462144 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

644462144 is a deficient number, since it is larger than the sum of its proper divisors (634392550).

644462144 is a wasteful number, since it uses less digits than its factorization.

644462144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10069733 (or 10069723 counting only the distinct ones).

The product of its digits is 73728, while the sum is 35.

The square root of 644462144 is about 25386.2589603116. The cubic root of 644462144 is about 863.7720306184.

The spelling of 644462144 in words is "six hundred forty-four million, four hundred sixty-two thousand, one hundred forty-four".