644236322 has 4 divisors (see below), whose sum is σ = 966354486. Its totient is φ = 322118160.

The previous prime is 644236309. The next prime is 644236331. The reversal of 644236322 is 223632446.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 223632446 = 2 ⋅111816223.

It can be written as a sum of positive squares in only one way, i.e., 454926241 + 189310081 = 21329^2 + 13759^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161059079 + ... + 161059082.

Almost surely, 2^644236322 is an apocalyptic number.

644236322 is a deficient number, since it is larger than the sum of its proper divisors (322118164).

644236322 is a wasteful number, since it uses less digits than its factorization.

644236322 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322118163.

The product of its digits is 41472, while the sum is 32.

The square root of 644236322 is about 25381.8108495040. The cubic root of 644236322 is about 863.6711291577.

Adding to 644236322 its reverse (223632446), we get a palindrome (867868768).

The spelling of 644236322 in words is "six hundred forty-four million, two hundred thirty-six thousand, three hundred twenty-two".