644673130 has 16 divisors (see below), whose sum is σ = 1166826024. Its totient is φ = 256443840.

The previous prime is 644673109. The next prime is 644673137. The reversal of 644673130 is 31376446.

It can be written as a sum of positive squares in 4 ways, for example, as 345625281 + 299047849 = 18591^2 + 17293^2 .

It is not an unprimeable number, because it can be changed into a prime (644673137) 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 7 ways as a sum of consecutive naturals, for example, 176277 + ... + 179896.

Almost surely, 2^644673130 is an apocalyptic number.

644673130 is a deficient number, since it is larger than the sum of its proper divisors (522152894).

644673130 is a wasteful number, since it uses less digits than its factorization.

644673130 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356361.

The product of its (nonzero) digits is 36288, while the sum is 34.

The square root of 644673130 is about 25390.4141360475. The cubic root of 644673130 is about 863.8662817823.

The spelling of 644673130 in words is "six hundred forty-four million, six hundred seventy-three thousand, one hundred thirty".