639763697637 has 12 divisors (see below), whose sum is σ = 936762066604. Its totient is φ = 420666540480.

The previous prime is 639763697627. The next prime is 639763697653. The reversal of 639763697637 is 736796367936.

It can be written as a sum of positive squares in 2 ways, for example, as 521354758401 + 118408939236 = 722049^2 + 344106^2 .

It is not a de Polignac number, because 639763697637 - 2²⁸ = 639495262181 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639763697627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 486881914 + ... + 486883227.

Almost surely, 2^639763697637 is an apocalyptic number.

It is an amenable number.

639763697637 is a deficient number, since it is larger than the sum of its proper divisors (296998368967).

639763697637 is a wasteful number, since it uses less digits than its factorization.

639763697637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 973765220 (or 973765217 counting only the distinct ones).

The product of its digits is 972182736, while the sum is 72.

The spelling of 639763697637 in words is "six hundred thirty-nine billion, seven hundred sixty-three million, six hundred ninety-seven thousand, six hundred thirty-seven".