639573149 has 2 divisors, whose sum is σ = 639573150. Its totient is φ = 639573148.

The previous prime is 639573097. The next prime is 639573169. The reversal of 639573149 is 941375936.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 594481924 + 45091225 = 24382^2 + 6715^2 .

It is a cyclic number.

It is not a de Polignac number, because 639573149 - 2⁸ = 639572893 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639573169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319786574 + 319786575.

It is an arithmetic number, because the mean of its divisors is an integer number (319786575).

Almost surely, 2^639573149 is an apocalyptic number.

It is an amenable number.

639573149 is a deficient number, since it is larger than the sum of its proper divisors (1).

639573149 is an equidigital number, since it uses as much as digits as its factorization.

639573149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 612360, while the sum is 47.

The square root of 639573149 is about 25289.7834905718. The cubic root of 639573149 is about 861.5822453614.

The spelling of 639573149 in words is "six hundred thirty-nine million, five hundred seventy-three thousand, one hundred forty-nine".