644406002 has 32 divisors (see below), whose sum is σ = 1010257920. Its totient is φ = 308065680.

The previous prime is 644405989. The next prime is 644406031. The reversal of 644406002 is 200604446.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 794177 + ... + 794987.

It is an arithmetic number, because the mean of its divisors is an integer number (31570560).

Almost surely, 2^644406002 is an apocalyptic number.

644406002 is a deficient number, since it is larger than the sum of its proper divisors (365851918).

644406002 is a wasteful number, since it uses less digits than its factorization.

644406002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1046.

The product of its (nonzero) digits is 4608, while the sum is 26.

The square root of 644406002 is about 25385.1531805502. The cubic root of 644406002 is about 863.7469475327.

The spelling of 644406002 in words is "six hundred forty-four million, four hundred six thousand, two".