639297797 has 2 divisors, whose sum is σ = 639297798. Its totient is φ = 639297796.

The previous prime is 639297793. The next prime is 639297809. The reversal of 639297797 is 797792936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 601671841 + 37625956 = 24529^2 + 6134^2 .

It is a cyclic number.

It is not a de Polignac number, because 639297797 - 2² = 639297793 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639297793) 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, 319648898 + 319648899.

It is an arithmetic number, because the mean of its divisors is an integer number (319648899).

Almost surely, 2^639297797 is an apocalyptic number.

It is an amenable number.

639297797 is a deficient number, since it is larger than the sum of its proper divisors (1).

639297797 is an equidigital number, since it uses as much as digits as its factorization.

639297797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9001692, while the sum is 59.

The square root of 639297797 is about 25284.3389670365. The cubic root of 639297797 is about 861.4585834844.

The spelling of 639297797 in words is "six hundred thirty-nine million, two hundred ninety-seven thousand, seven hundred ninety-seven".