645839204 has 6 divisors (see below), whose sum is σ = 1130218614. Its totient is φ = 322919600.

The previous prime is 645839191. The next prime is 645839209. The reversal of 645839204 is 402938546.

It can be written as a sum of positive squares in only one way, i.e., 645261604 + 577600 = 25402^2 + 760^2 .

It is not an unprimeable number, because it can be changed into a prime (645839209) 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 as a sum of consecutive naturals, namely, 80729897 + ... + 80729904.

It is an arithmetic number, because the mean of its divisors is an integer number (188369769).

Almost surely, 2^645839204 is an apocalyptic number.

It is an amenable number.

645839204 is a deficient number, since it is larger than the sum of its proper divisors (484379410).

645839204 is a wasteful number, since it uses less digits than its factorization.

645839204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161459805 (or 161459803 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 41.

The square root of 645839204 is about 25413.3666404119. The cubic root of 645839204 is about 864.3868170349.

The spelling of 645839204 in words is "six hundred forty-five million, eight hundred thirty-nine thousand, two hundred four".