644466044 has 12 divisors (see below), whose sum is σ = 1155323568. Its totient is φ = 314373600.

The previous prime is 644466041. The next prime is 644466047. The reversal of 644466044 is 440664446.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (644466041) and next prime (644466047).

It is a junction number, because it is equal to n+sod(n) for n = 644465989 and 644466007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644466041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1964672 + ... + 1964999.

It is an arithmetic number, because the mean of its divisors is an integer number (96276964).

Almost surely, 2^644466044 is an apocalyptic number.

It is an amenable number.

644466044 is a deficient number, since it is larger than the sum of its proper divisors (510857524).

644466044 is a wasteful number, since it uses less digits than its factorization.

644466044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3929716 (or 3929714 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 38.

The square root of 644466044 is about 25386.3357734038. The cubic root of 644466044 is about 863.7737730037.

The spelling of 644466044 in words is "six hundred forty-four million, four hundred sixty-six thousand, forty-four".