644246444 has 12 divisors (see below), whose sum is σ = 1128135624. Its totient is φ = 321921984.

The previous prime is 644246413. The next prime is 644246453. The reversal of 644246444 is 444642446.

It is a junction number, because it is equal to n+sod(n) for n = 644246398 and 644246407.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42989 + ... + 56004.

It is an arithmetic number, because the mean of its divisors is an integer number (94011302).

Almost surely, 2^644246444 is an apocalyptic number.

It is an amenable number.

644246444 is a deficient number, since it is larger than the sum of its proper divisors (483889180).

644246444 is a wasteful number, since it uses less digits than its factorization.

644246444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100624 (or 100622 counting only the distinct ones).

The product of its digits is 294912, while the sum is 38.

The square root of 644246444 is about 25382.0102434776. The cubic root of 644246444 is about 863.6756523599.

The spelling of 644246444 in words is "six hundred forty-four million, two hundred forty-six thousand, four hundred forty-four".