13291937847721 has 27 divisors (see below), whose sum is σ = 14534362058853. Its totient is φ = 12150175571040.

The previous prime is 13291937847719. The next prime is 13291937847737. The reversal of 13291937847721 is 12774873919231.

The square root of 13291937847721 is 3645811.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 19497933225 + 13272439914496 = 139635^2 + 3643136^2 .

It is not a de Polignac number, because 13291937847721 - 2¹ = 13291937847719 is a prime.

It is a super-2 number, since 2×13291937847721² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (13291937847751) 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 26 ways as a sum of consecutive naturals, for example, 5071321791 + ... + 5071324411.

Almost surely, 2^{13291937847721} is an apocalyptic number.

13291937847721 is the 3645811-st square number.

13291937847721 is the 1822906-th centered octagonal number.

It is an amenable number.

13291937847721 is a deficient number, since it is larger than the sum of its proper divisors (1242424211132).

13291937847721 is an frugal number, since it uses more digits than its factorization.

13291937847721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5482 (or 2741 counting only the distinct ones).

The product of its digits is 32006016, while the sum is 64.

Multiplying 13291937847721 by its sum of digits (64), we get a square (850684022254144 = 29166488²).

The spelling of 13291937847721 in words is "thirteen trillion, two hundred ninety-one billion, nine hundred thirty-seven million, eight hundred forty-seven thousand, seven hundred twenty-one".