1644434864 has 20 divisors (see below), whose sum is σ = 3324619056. Its totient is φ = 786468672.

The previous prime is 1644434839. The next prime is 1644434893. The reversal of 1644434864 is 4684344461.

It is a happy number.

It is a hoax number, since the sum of its digits (44) coincides with the sum of the digits of its distinct prime factors.

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, 2233919 + ... + 2234654.

Almost surely, 2^1644434864 is an apocalyptic number.

It is an amenable number.

1644434864 is an abundant number, since it is smaller than the sum of its proper divisors (1680184192).

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

1644434864 is a wasteful number, since it uses less digits than its factorization.

1644434864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4468604 (or 4468598 counting only the distinct ones).

The product of its digits is 884736, while the sum is 44.

The square root of 1644434864 is about 40551.6320756637. The cubic root of 1644434864 is about 1180.3357428234.

The spelling of 1644434864 in words is "one billion, six hundred forty-four million, four hundred thirty-four thousand, eight hundred sixty-four".