644797674 has 12 divisors (see below), whose sum is σ = 1397061666. Its totient is φ = 214932552.

The previous prime is 644797651. The next prime is 644797679. The reversal of 644797674 is 476797446.

It can be written as a sum of positive squares in only one way, i.e., 582498225 + 62299449 = 24135^2 + 7893^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 644797674.

It is not an unprimeable number, because it can be changed into a prime (644797679) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 17911029 + ... + 17911064.

Almost surely, 2^644797674 is an apocalyptic number.

644797674 is an abundant number, since it is smaller than the sum of its proper divisors (752263992).

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

644797674 is a wasteful number, since it uses less digits than its factorization.

644797674 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35822101 (or 35822098 counting only the distinct ones).

The product of its digits is 7112448, while the sum is 54.

The square root of 644797674 is about 25392.8665967433. The cubic root of 644797674 is about 863.9219081297.

The spelling of 644797674 in words is "six hundred forty-four million, seven hundred ninety-seven thousand, six hundred seventy-four".