644749698 has 16 divisors (see below), whose sum is σ = 1289845440. Its totient is φ = 214858896.

The previous prime is 644749673. The next prime is 644749733. The reversal of 644749698 is 896947446.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14163 + ... + 38601.

It is an arithmetic number, because the mean of its divisors is an integer number (80615340).

Almost surely, 2^644749698 is an apocalyptic number.

644749698 is an abundant number, since it is smaller than the sum of its proper divisors (645095742).

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

644749698 is a wasteful number, since it uses less digits than its factorization.

644749698 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28841.

The product of its digits is 10450944, while the sum is 57.

The square root of 644749698 is about 25391.9219044168. The cubic root of 644749698 is about 863.9004809714.

The spelling of 644749698 in words is "six hundred forty-four million, seven hundred forty-nine thousand, six hundred ninety-eight".