644126624 has 12 divisors (see below), whose sum is σ = 1268124354. Its totient is φ = 322063296.

The previous prime is 644126603. The next prime is 644126641. The reversal of 644126624 is 426621446.

It can be written as a sum of positive squares in only one way, i.e., 331968400 + 312158224 = 18220^2 + 17668^2 .

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, 10064447 + ... + 10064510.

Almost surely, 2^644126624 is an apocalyptic number.

It is an amenable number.

644126624 is a deficient number, since it is larger than the sum of its proper divisors (623997730).

644126624 is a wasteful number, since it uses less digits than its factorization.

644126624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20128967 (or 20128959 counting only the distinct ones).

The product of its digits is 55296, while the sum is 35.

The square root of 644126624 is about 25379.6498005784. The cubic root of 644126624 is about 863.6221055462.

The spelling of 644126624 in words is "six hundred forty-four million, one hundred twenty-six thousand, six hundred twenty-four".