644221934 has 16 divisors (see below), whose sum is σ = 981369648. Its totient is φ = 317115072.

The previous prime is 644221909. The next prime is 644221969. The reversal of 644221934 is 439122446.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644221894 and 644221903.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 81944 + ... + 89460.

It is an arithmetic number, because the mean of its divisors is an integer number (61335603).

Almost surely, 2^644221934 is an apocalyptic number.

644221934 is a deficient number, since it is larger than the sum of its proper divisors (337147714).

644221934 is a wasteful number, since it uses less digits than its factorization.

644221934 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8179.

The product of its digits is 41472, while the sum is 35.

The square root of 644221934 is about 25381.5274166075. The cubic root of 644221934 is about 863.6646995333.

The spelling of 644221934 in words is "six hundred forty-four million, two hundred twenty-one thousand, nine hundred thirty-four".