644668222 has 8 divisors (see below), whose sum is σ = 1054911672. Its totient is φ = 293031000.

The previous prime is 644668201. The next prime is 644668253. The reversal of 644668222 is 222866446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14651529 + ... + 14651572.

It is an arithmetic number, because the mean of its divisors is an integer number (131863959).

Almost surely, 2^644668222 is an apocalyptic number.

644668222 is a deficient number, since it is larger than the sum of its proper divisors (410243450).

644668222 is a wasteful number, since it uses less digits than its factorization.

644668222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29303114.

The product of its digits is 221184, while the sum is 40.

The square root of 644668222 is about 25390.3174852147. The cubic root of 644668222 is about 863.8640895258.

It can be divided in two parts, 644 and 668222, that added together give a palindrome (668866).

The spelling of 644668222 in words is "six hundred forty-four million, six hundred sixty-eight thousand, two hundred twenty-two".