644665370907 has 8 divisors (see below), whose sum is σ = 859564895040. Its totient is φ = 429771380360.

The previous prime is 644665370893. The next prime is 644665370917. The reversal of 644665370907 is 709073566446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644665370907 - 2²⁴ = 644648593691 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644665370917) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1103469 + ... + 1583342.

It is an arithmetic number, because the mean of its divisors is an integer number (107445611880).

Almost surely, 2^644665370907 is an apocalyptic number.

644665370907 is a deficient number, since it is larger than the sum of its proper divisors (214899524133).

644665370907 is a wasteful number, since it uses less digits than its factorization.

644665370907 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2766793.

The product of its (nonzero) digits is 22861440, while the sum is 57.

The spelling of 644665370907 in words is "six hundred forty-four billion, six hundred sixty-five million, three hundred seventy thousand, nine hundred seven".