644463696700 has 18 divisors (see below), whose sum is σ = 1398486222056. Its totient is φ = 257785478640.

The previous prime is 644463696637. The next prime is 644463696707. The reversal of 644463696700 is 7696364446.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644463696707) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3222318384 + ... + 3222318583.

Almost surely, 2^644463696700 is an apocalyptic number.

It is an amenable number.

644463696700 is an abundant number, since it is smaller than the sum of its proper divisors (754022525356).

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

644463696700 is a wasteful number, since it uses less digits than its factorization.

644463696700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6444636981 (or 6444636974 counting only the distinct ones).

The product of its (nonzero) digits is 15676416, while the sum is 55.

The spelling of 644463696700 in words is "six hundred forty-four billion, four hundred sixty-three million, six hundred ninety-six thousand, seven hundred".