639304213 has 2 divisors, whose sum is σ = 639304214. Its totient is φ = 639304212.

The previous prime is 639304187. The next prime is 639304243. The reversal of 639304213 is 312403936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 606045924 + 33258289 = 24618^2 + 5767^2 .

It is a cyclic number.

It is not a de Polignac number, because 639304213 - 2⁵ = 639304181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639304243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319652106 + 319652107.

It is an arithmetic number, because the mean of its divisors is an integer number (319652107).

Almost surely, 2^639304213 is an apocalyptic number.

It is an amenable number.

639304213 is a deficient number, since it is larger than the sum of its proper divisors (1).

639304213 is an equidigital number, since it uses as much as digits as its factorization.

639304213 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 31.

The square root of 639304213 is about 25284.4658436756. The cubic root of 639304213 is about 861.4614653442.

The spelling of 639304213 in words is "six hundred thirty-nine million, three hundred four thousand, two hundred thirteen".