645019204 has 12 divisors (see below), whose sum is σ = 1130617404. Its totient is φ = 321985664.

The previous prime is 645019181. The next prime is 645019213. The reversal of 645019204 is 402910546.

It can be written as a sum of positive squares in 2 ways, for example, as 122988100 + 522031104 = 11090^2 + 22848^2 .

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 3 ways as a sum of consecutive naturals, for example, 128209 + ... + 133144.

It is an arithmetic number, because the mean of its divisors is an integer number (94218117).

Almost surely, 2^645019204 is an apocalyptic number.

It is an amenable number.

645019204 is a deficient number, since it is larger than the sum of its proper divisors (485598200).

645019204 is a wasteful number, since it uses less digits than its factorization.

645019204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261974 (or 261972 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 645019204 is about 25397.2282739672. The cubic root of 645019204 is about 864.0208346170.

The spelling of 645019204 in words is "six hundred forty-five million, nineteen thousand, two hundred four".