644562534 has 64 divisors (see below), whose sum is σ = 1677127680. Its totient is φ = 160137120.

The previous prime is 644562491. The next prime is 644562547. The reversal of 644562534 is 435265446.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644562492 and 644562501.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19704 + ... + 40955.

It is an arithmetic number, because the mean of its divisors is an integer number (26205120).

Almost surely, 2^644562534 is an apocalyptic number.

644562534 is an abundant number, since it is smaller than the sum of its proper divisors (1032565146).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644562534 is a wasteful number, since it uses less digits than its factorization.

644562534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60705.

The product of its digits is 345600, while the sum is 39.

The square root of 644562534 is about 25388.2361340838. The cubic root of 644562534 is about 863.8168791652.

The spelling of 644562534 in words is "six hundred forty-four million, five hundred sixty-two thousand, five hundred thirty-four".