644633632 has 24 divisors (see below), whose sum is σ = 1271358396. Its totient is φ = 321748992.

The previous prime is 644633629. The next prime is 644633641. The reversal of 644633632 is 236336446.

It can be written as a sum of positive squares in 2 ways, for example, as 571975056 + 72658576 = 23916^2 + 8524^2 .

It is a super-2 number, since 2×644633632² = 831105039011022848, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644633591 and 644633600.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1008 + ... + 35920.

Almost surely, 2^644633632 is an apocalyptic number.

It is an amenable number.

644633632 is a deficient number, since it is larger than the sum of its proper divisors (626724764).

644633632 is a wasteful number, since it uses less digits than its factorization.

644633632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35500 (or 35492 counting only the distinct ones).

The product of its digits is 186624, while the sum is 37.

The square root of 644633632 is about 25389.6363109045. The cubic root of 644633632 is about 863.8486388944.

The spelling of 644633632 in words is "six hundred forty-four million, six hundred thirty-three thousand, six hundred thirty-two".