644023722 has 16 divisors (see below), whose sum is σ = 1291296672. Its totient is φ = 214133040.

The previous prime is 644023703. The next prime is 644023727. The reversal of 644023722 is 227320446.

It is a self number, because there is not a number n which added to its sum of digits gives 644023722.

It is not an unprimeable number, because it can be changed into a prime (644023727) 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 7 ways as a sum of consecutive naturals, for example, 132804 + ... + 137567.

It is an arithmetic number, because the mean of its divisors is an integer number (80706042).

Almost surely, 2^644023722 is an apocalyptic number.

644023722 is an abundant number, since it is smaller than the sum of its proper divisors (647272950).

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

644023722 is a wasteful number, since it uses less digits than its factorization.

644023722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 270773.

The product of its (nonzero) digits is 16128, while the sum is 30.

The square root of 644023722 is about 25377.6224654714. The cubic root of 644023722 is about 863.5761139811.

The spelling of 644023722 in words is "six hundred forty-four million, twenty-three thousand, seven hundred twenty-two".