644462976 has 96 divisors (see below), whose sum is σ = 1807083000. Its totient is φ = 203470848.

The previous prime is 644462947. The next prime is 644462977. The reversal of 644462976 is 679264446.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644462977) by changing a digit.

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 in 11 ways as a sum of consecutive naturals, for example, 136300 + ... + 140948.

Almost surely, 2^644462976 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644462976, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (903541500).

644462976 is an abundant number, since it is smaller than the sum of its proper divisors (1162620024).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644462976 is a wasteful number, since it uses less digits than its factorization.

644462976 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4704 (or 4673 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 48.

The square root of 644462976 is about 25386.2753471241. The cubic root of 644462976 is about 863.7724023278.

The spelling of 644462976 in words is "six hundred forty-four million, four hundred sixty-two thousand, nine hundred seventy-six".