644379827 has 32 divisors (see below), whose sum is σ = 823331712. Its totient is φ = 490696704.

The previous prime is 644379763. The next prime is 644379859. The reversal of 644379827 is 728973446.

644379827 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 644379827 - 2⁶ = 644379763 is a prime.

It is a super-2 number, since 2×644379827² = 830450722889099858, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (644379427) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 325613 + ... + 327585.

It is an arithmetic number, because the mean of its divisors is an integer number (25729116).

Almost surely, 2^644379827 is an apocalyptic number.

644379827 is a deficient number, since it is larger than the sum of its proper divisors (178951885).

644379827 is a wasteful number, since it uses less digits than its factorization.

644379827 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2127.

The product of its digits is 2032128, while the sum is 50.

The square root of 644379827 is about 25384.6376180555. The cubic root of 644379827 is about 863.7352525855.

The spelling of 644379827 in words is "six hundred forty-four million, three hundred seventy-nine thousand, eight hundred twenty-seven".