644890472 has 8 divisors (see below), whose sum is σ = 1209169650. Its totient is φ = 322445232.

The previous prime is 644890471. The next prime is 644890481. The reversal of 644890472 is 274098446.

644890472 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 376127236 + 268763236 = 19394^2 + 16394^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (644890471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40305647 + ... + 40305662.

Almost surely, 2^644890472 is an apocalyptic number.

It is an amenable number.

644890472 is a deficient number, since it is larger than the sum of its proper divisors (564279178).

644890472 is a wasteful number, since it uses less digits than its factorization.

644890472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80611315 (or 80611311 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 44.

The square root of 644890472 is about 25394.6937764565. The cubic root of 644890472 is about 863.9633507831.

The spelling of 644890472 in words is "six hundred forty-four million, eight hundred ninety thousand, four hundred seventy-two".