13381746721 has 32 divisors (see below), whose sum is σ = 16546304000. Its totient is φ = 10568143872.

The previous prime is 13381746617. The next prime is 13381746737. The reversal of 13381746721 is 12764718331.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 13381746721 - 2¹³ = 13381738529 is a prime.

It is a super-2 number, since 2×13381746721² (a number of 21 digits) contains 22 as substring.

It is the 115680-th Hogben number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13381746121) by changing a digit.

It is a nontrivial repunit in base 115679.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 694465 + ... + 713473.

It is an arithmetic number, because the mean of its divisors is an integer number (517072000).

Almost surely, 2^13381746721 is an apocalyptic number.

It is an amenable number.

13381746721 is a deficient number, since it is larger than the sum of its proper divisors (3164557279).

13381746721 is a wasteful number, since it uses less digits than its factorization.

13381746721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19181.

The product of its digits is 169344, while the sum is 43.

The spelling of 13381746721 in words is "thirteen billion, three hundred eighty-one million, seven hundred forty-six thousand, seven hundred twenty-one".