644374942290 has 48 divisors (see below), whose sum is σ = 1773926315928. Its totient is φ = 161725475328.

The previous prime is 644374942279. The next prime is 644374942301. The reversal of 644374942290 is 92249473446.

644374942290 is a `hidden beast` number, since 6 + 4 + 43 + 7 + 494 + 22 + 90 = 666.

It is an interprime number because it is at equal distance from previous prime (644374942279) and next prime (644374942301).

It can be written as a sum of positive squares in 4 ways, for example, as 552763997361 + 91610944929 = 743481^2 + 302673^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 210578517 + ... + 210581576.

Almost surely, 2^644374942290 is an apocalyptic number.

644374942290 is an abundant number, since it is smaller than the sum of its proper divisors (1129551373638).

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

644374942290 is a wasteful number, since it uses less digits than its factorization.

644374942290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 421160123 (or 421160120 counting only the distinct ones).

The product of its (nonzero) digits is 10450944, while the sum is 54.

The spelling of 644374942290 in words is "six hundred forty-four billion, three hundred seventy-four million, nine hundred forty-two thousand, two hundred ninety".