13386617721 has 6 divisors (see below), whose sum is σ = 19336225610. Its totient is φ = 8924411808.

The previous prime is 13386617693. The next prime is 13386617743. The reversal of 13386617721 is 12771668331.

13386617721 is a `hidden beast` number, since 1 + 3 + 3 + 8 + 6 + 617 + 7 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 9308390400 + 4078227321 = 96480^2 + 63861^2 .

It is not a de Polignac number, because 13386617721 - 2⁷ = 13386617593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13386617791) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 743700976 + ... + 743700993.

Almost surely, 2^13386617721 is an apocalyptic number.

It is an amenable number.

13386617721 is a deficient number, since it is larger than the sum of its proper divisors (5949607889).

13386617721 is a wasteful number, since it uses less digits than its factorization.

13386617721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1487401975 (or 1487401972 counting only the distinct ones).

The product of its digits is 254016, while the sum is 45.

The spelling of 13386617721 in words is "thirteen billion, three hundred eighty-six million, six hundred seventeen thousand, seven hundred twenty-one".