644102245444 has 48 divisors (see below), whose sum is σ = 1312525298560. Its totient is φ = 270854357760.

The previous prime is 644102245433. The next prime is 644102245481. The reversal of 644102245444 is 444542201446.

It is a junction number, because it is equal to n+sod(n) for n = 644102245397 and 644102245406.

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, 237559 + ... + 1159585.

Almost surely, 2^644102245444 is an apocalyptic number.

It is an amenable number.

644102245444 is an abundant number, since it is smaller than the sum of its proper divisors (668423053116).

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

644102245444 is a wasteful number, since it uses less digits than its factorization.

644102245444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 922508 (or 922506 counting only the distinct ones).

The product of its (nonzero) digits is 491520, while the sum is 40.

The spelling of 644102245444 in words is "six hundred forty-four billion, one hundred two million, two hundred forty-five thousand, four hundred forty-four".