644789122 has 4 divisors (see below), whose sum is σ = 967183686. Its totient is φ = 322394560.

The previous prime is 644789081. The next prime is 644789129. The reversal of 644789122 is 221987446.

644789122 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 437688241 + 207100881 = 20921^2 + 14391^2 .

It is not an unprimeable number, because it can be changed into a prime (644789129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161197279 + ... + 161197282.

Almost surely, 2^644789122 is an apocalyptic number.

644789122 is a deficient number, since it is larger than the sum of its proper divisors (322394564).

644789122 is a wasteful number, since it uses less digits than its factorization.

644789122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322394563.

The product of its digits is 193536, while the sum is 43.

The square root of 644789122 is about 25392.6982024361. The cubic root of 644789122 is about 863.9180886924.

The spelling of 644789122 in words is "six hundred forty-four million, seven hundred eighty-nine thousand, one hundred twenty-two".