644297793 has 4 divisors (see below), whose sum is σ = 859063728. Its totient is φ = 429531860.

The previous prime is 644297783. The next prime is 644297833. The reversal of 644297793 is 397792446.

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 644297793 - 2⁴ = 644297777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644297713) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107382963 + ... + 107382968.

It is an arithmetic number, because the mean of its divisors is an integer number (214765932).

Almost surely, 2^644297793 is an apocalyptic number.

It is an amenable number.

644297793 is a deficient number, since it is larger than the sum of its proper divisors (214765935).

644297793 is a wasteful number, since it uses less digits than its factorization.

644297793 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214765934.

The product of its digits is 2286144, while the sum is 51.

The square root of 644297793 is about 25383.0217468291. The cubic root of 644297793 is about 863.6985978767.

The spelling of 644297793 in words is "six hundred forty-four million, two hundred ninety-seven thousand, seven hundred ninety-three".