644425131 has 16 divisors (see below), whose sum is σ = 1002875904. Its totient is φ = 360407424.

The previous prime is 644425129. The next prime is 644425139. The reversal of 644425131 is 131524446.

644425131 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644425131 - 2¹ = 644425129 is a prime.

It is a super-2 number, since 2×644425131² = 830567498928734322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (644425139) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 325470 + ... + 327443.

It is an arithmetic number, because the mean of its divisors is an integer number (62679744).

Almost surely, 2^644425131 is an apocalyptic number.

644425131 is a deficient number, since it is larger than the sum of its proper divisors (358450773).

644425131 is a wasteful number, since it uses less digits than its factorization.

644425131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 652970.

The product of its digits is 11520, while the sum is 30.

The square root of 644425131 is about 25385.5299531052. The cubic root of 644425131 is about 863.7554941383.

Adding to 644425131 its reverse (131524446), we get a palindrome (775949577).

The spelling of 644425131 in words is "six hundred forty-four million, four hundred twenty-five thousand, one hundred thirty-one".