644754979 has 4 divisors (see below), whose sum is σ = 703369080. Its totient is φ = 586140880.

The previous prime is 644754973. The next prime is 644754991. The reversal of 644754979 is 979457446.

644754979 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 644754979 - 2¹⁷ = 644623907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644754973) 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, 29307034 + ... + 29307055.

It is an arithmetic number, because the mean of its divisors is an integer number (175842270).

Almost surely, 2^644754979 is an apocalyptic number.

644754979 is a deficient number, since it is larger than the sum of its proper divisors (58614101).

644754979 is a wasteful number, since it uses less digits than its factorization.

644754979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58614100.

The product of its digits is 7620480, while the sum is 55.

The square root of 644754979 is about 25392.0258939692. The cubic root of 644754979 is about 863.9028396366.

The spelling of 644754979 in words is "six hundred forty-four million, seven hundred fifty-four thousand, nine hundred seventy-nine".