644233716 has 96 divisors (see below), whose sum is σ = 1932026880. Its totient is φ = 181831392.

The previous prime is 644233691. The next prime is 644233727. The reversal of 644233716 is 617332446.

It is a happy number.

644233716 is a `hidden beast` number, since 644 + 2 + 3 + 3 + 7 + 1 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

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 31 ways as a sum of consecutive naturals, for example, 57615 + ... + 67881.

It is an arithmetic number, because the mean of its divisors is an integer number (20125280).

Almost surely, 2^644233716 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 644233716, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (966013440).

644233716 is an abundant number, since it is smaller than the sum of its proper divisors (1287793164).

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

644233716 is a wasteful number, since it uses less digits than its factorization.

644233716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10370 (or 10362 counting only the distinct ones).

The product of its digits is 72576, while the sum is 36.

The square root of 644233716 is about 25381.7595134774. The cubic root of 644233716 is about 863.6699646109.

The spelling of 644233716 in words is "six hundred forty-four million, two hundred thirty-three thousand, seven hundred sixteen".