644353337 has 4 divisors (see below), whose sum is σ = 655274640. Its totient is φ = 633432036.

The previous prime is 644353279. The next prime is 644353343. The reversal of 644353337 is 733353446.

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 644353337 - 2⁶ = 644353273 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 644353337.

It is not an unprimeable number, because it can be changed into a prime (644353387) 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, 5460563 + ... + 5460680.

It is an arithmetic number, because the mean of its divisors is an integer number (163818660).

Almost surely, 2^644353337 is an apocalyptic number.

It is an amenable number.

644353337 is a deficient number, since it is larger than the sum of its proper divisors (10921303).

644353337 is a wasteful number, since it uses less digits than its factorization.

644353337 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10921302.

The product of its digits is 272160, while the sum is 38.

The square root of 644353337 is about 25384.1158404227. The cubic root of 644353337 is about 863.7234165744.

The spelling of 644353337 in words is "six hundred forty-four million, three hundred fifty-three thousand, three hundred thirty-seven".