639045977 has 2 divisors, whose sum is σ = 639045978. Its totient is φ = 639045976.

The previous prime is 639045947. The next prime is 639046013. The reversal of 639045977 is 779540936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 513067801 + 125978176 = 22651^2 + 11224^2 .

It is a cyclic number.

It is not a de Polignac number, because 639045977 - 2¹² = 639041881 is a prime.

It is not a weakly prime, because it can be changed into another prime (639045917) by changing a digit.

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 as a sum of consecutive naturals, namely, 319522988 + 319522989.

It is an arithmetic number, because the mean of its divisors is an integer number (319522989).

Almost surely, 2^639045977 is an apocalyptic number.

It is an amenable number.

639045977 is a deficient number, since it is larger than the sum of its proper divisors (1).

639045977 is an equidigital number, since it uses as much as digits as its factorization.

639045977 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1428840, while the sum is 50.

The square root of 639045977 is about 25279.3587141763. The cubic root of 639045977 is about 861.3454588493.

The spelling of 639045977 in words is "six hundred thirty-nine million, forty-five thousand, nine hundred seventy-seven".