644223569 has 4 divisors (see below), whose sum is σ = 702789360. Its totient is φ = 585657780.

The previous prime is 644223523. The next prime is 644223577. The reversal of 644223569 is 965322446.

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 a de Polignac number, because none of the positive numbers 2^k-644223569 is a prime.

It is a super-2 number, since 2×644223569² = 830048013710195522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644223599) 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, 29282879 + ... + 29282900.

It is an arithmetic number, because the mean of its divisors is an integer number (175697340).

Almost surely, 2^644223569 is an apocalyptic number.

It is an amenable number.

644223569 is a deficient number, since it is larger than the sum of its proper divisors (58565791).

644223569 is a wasteful number, since it uses less digits than its factorization.

644223569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58565790.

The product of its digits is 311040, while the sum is 41.

The square root of 644223569 is about 25381.5596250506. The cubic root of 644223569 is about 863.6654301773.

The spelling of 644223569 in words is "six hundred forty-four million, two hundred twenty-three thousand, five hundred sixty-nine".