644369 has 4 divisors (see below), whose sum is σ = 702960. Its totient is φ = 585780.

The previous prime is 644363. The next prime is 644377. The reversal of 644369 is 963446.

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 644369 - 2⁴ = 644353 is a prime.

It is a super-2 number, since 2×644369² = 830422816322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644363) 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, 29279 + ... + 29300.

It is an arithmetic number, because the mean of its divisors is an integer number (175740).

2⁶⁴⁴³⁶⁹ is an apocalyptic number.

It is an amenable number.

644369 is a deficient number, since it is larger than the sum of its proper divisors (58591).

644369 is a wasteful number, since it uses less digits than its factorization.

644369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58590.

The product of its digits is 15552, while the sum is 32.

The square root of 644369 is about 802.7259806435. The cubic root of 644369 is about 86.3730415007.

The spelling of 644369 in words is "six hundred forty-four thousand, three hundred sixty-nine".