644630645436 has 24 divisors (see below), whose sum is σ = 1505833956480. Its totient is φ = 214634626992.

The previous prime is 644630645413. The next prime is 644630645467. The reversal of 644630645436 is 634546036446.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30270766 + ... + 30292053.

It is an arithmetic number, because the mean of its divisors is an integer number (62743081520).

Almost surely, 2^644630645436 is an apocalyptic number.

It is an amenable number.

644630645436 is an abundant number, since it is smaller than the sum of its proper divisors (861203311044).

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

644630645436 is a wasteful number, since it uses less digits than its factorization.

644630645436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60563713 (or 60563711 counting only the distinct ones).

The product of its (nonzero) digits is 14929920, while the sum is 51.

The spelling of 644630645436 in words is "six hundred forty-four billion, six hundred thirty million, six hundred forty-five thousand, four hundred thirty-six".