639697333697 has 12 divisors (see below), whose sum is σ = 655010748900. Its totient is φ = 624734062848.

The previous prime is 639697333679. The next prime is 639697333711. The reversal of 639697333697 is 796333796936.

It can be written as a sum of positive squares in 2 ways, for example, as 83299195456 + 556398138241 = 288616^2 + 745921^2 .

It is not a de Polignac number, because 639697333697 - 2⁸ = 639697333441 is a prime.

It is a Smith number, since the sum of its digits (71) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 639697333697.

It is not an unprimeable number, because it can be changed into a prime (639697332697) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16342253 + ... + 16381349.

It is an arithmetic number, because the mean of its divisors is an integer number (54584229075).

Almost surely, 2^639697333697 is an apocalyptic number.

It is an amenable number.

639697333697 is a deficient number, since it is larger than the sum of its proper divisors (15313415203).

639697333697 is an equidigital number, since it uses as much as digits as its factorization.

639697333697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48032 (or 47989 counting only the distinct ones).

The product of its digits is 624974616, while the sum is 71.

The spelling of 639697333697 in words is "six hundred thirty-nine billion, six hundred ninety-seven million, three hundred thirty-three thousand, six hundred ninety-seven".