644106713 has 4 divisors (see below), whose sum is σ = 644430288. Its totient is φ = 643783140.

The previous prime is 644106703. The next prime is 644106731. The reversal of 644106713 is 317601446.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 644106713 - 2⁶ = 644106649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 644106713.

It is not an unprimeable number, because it can be changed into a prime (644106703) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 158783 + ... + 162788.

It is an arithmetic number, because the mean of its divisors is an integer number (161107572).

Almost surely, 2^644106713 is an apocalyptic number.

It is an amenable number.

644106713 is a deficient number, since it is larger than the sum of its proper divisors (323575).

644106713 is a wasteful number, since it uses less digits than its factorization.

644106713 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323574.

The product of its (nonzero) digits is 12096, while the sum is 32.

The square root of 644106713 is about 25379.2575344512. The cubic root of 644106713 is about 863.6132068006.

The spelling of 644106713 in words is "six hundred forty-four million, one hundred six thousand, seven hundred thirteen".