636994867637 has 2 divisors, whose sum is σ = 636994867638. Its totient is φ = 636994867636.

The previous prime is 636994867631. The next prime is 636994867669. The reversal of 636994867637 is 736768499636.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 585827975236 + 51166892401 = 765394^2 + 226201^2 .

It is a cyclic number.

It is not a de Polignac number, because 636994867637 - 2⁶ = 636994867573 is a prime.

It is a super-2 number, since 2×636994867637² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (636994867631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318497433818 + 318497433819.

It is an arithmetic number, because the mean of its divisors is an integer number (318497433819).

Almost surely, 2^636994867637 is an apocalyptic number.

It is an amenable number.

636994867637 is a deficient number, since it is larger than the sum of its proper divisors (1).

636994867637 is an equidigital number, since it uses as much as digits as its factorization.

636994867637 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1481421312, while the sum is 74.

The spelling of 636994867637 in words is "six hundred thirty-six billion, nine hundred ninety-four million, eight hundred sixty-seven thousand, six hundred thirty-seven".