644234976 has 432 divisors, whose sum is σ = 2439964800. Its totient is φ = 157386240.

The previous prime is 644234953. The next prime is 644234989. The reversal of 644234976 is 679432446.

It is a happy number.

644234976 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 4634715 + ... + 4634853.

Almost surely, 2^644234976 is an apocalyptic number.

644234976 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644234976, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1219982400).

644234976 is an abundant number, since it is smaller than the sum of its proper divisors (1795729824).

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

644234976 is a wasteful number, since it uses less digits than its factorization.

644234976 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203 (or 181 counting only the distinct ones).

The product of its digits is 870912, while the sum is 45.

The square root of 644234976 is about 25381.7843344395. The cubic root of 644234976 is about 863.6705276692.

The spelling of 644234976 in words is "six hundred forty-four million, two hundred thirty-four thousand, nine hundred seventy-six".