13636768921 has 2 divisors, whose sum is σ = 13636768922. Its totient is φ = 13636768920.

The previous prime is 13636768913. The next prime is 13636768967. The reversal of 13636768921 is 12986763631.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12987793296 + 648975625 = 113964^2 + 25475^2 .

It is a cyclic number.

It is not a de Polignac number, because 13636768921 - 2³ = 13636768913 is a prime.

It is a super-2 number, since 2×13636768921² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (13636768021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6818384460 + 6818384461.

It is an arithmetic number, because the mean of its divisors is an integer number (6818384461).

Almost surely, 2^13636768921 is an apocalyptic number.

It is an amenable number.

13636768921 is a deficient number, since it is larger than the sum of its proper divisors (1).

13636768921 is an equidigital number, since it uses as much as digits as its factorization.

13636768921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1959552, while the sum is 52.

The spelling of 13636768921 in words is "thirteen billion, six hundred thirty-six million, seven hundred sixty-eight thousand, nine hundred twenty-one".