644004962542000 has 80 divisors (see below), whose sum is σ = 1593418046137632. Its totient is φ = 251611241145600.

The previous prime is 644004962541989. The next prime is 644004962542009. The reversal of 644004962542000 is 245269400446.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (644004962542009) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3744128899 + ... + 3744300898.

Almost surely, 2^{644004962542000} is an apocalyptic number.

It is an amenable number.

644004962542000 is an abundant number, since it is smaller than the sum of its proper divisors (949413083595632).

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

644004962542000 is a wasteful number, since it uses less digits than its factorization.

644004962542000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7488429863 (or 7488429847 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 46.

The spelling of 644004962542000 in words is "six hundred forty-four trillion, four billion, nine hundred sixty-two million, five hundred forty-two thousand".