13993176721 has 2 divisors, whose sum is σ = 13993176722. Its totient is φ = 13993176720.

The previous prime is 13993176689. The next prime is 13993176737. The reversal of 13993176721 is 12767139931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13141412496 + 851764225 = 114636^2 + 29185^2 .

It is a cyclic number.

It is not a de Polignac number, because 13993176721 - 2⁵ = 13993176689 is a prime.

It is not a weakly prime, because it can be changed into another prime (13993176751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6996588360 + 6996588361.

It is an arithmetic number, because the mean of its divisors is an integer number (6996588361).

Almost surely, 2^13993176721 is an apocalyptic number.

It is an amenable number.

13993176721 is a deficient number, since it is larger than the sum of its proper divisors (1).

13993176721 is an equidigital number, since it uses as much as digits as its factorization.

13993176721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 428652, while the sum is 49.

The spelling of 13993176721 in words is "thirteen billion, nine hundred ninety-three million, one hundred seventy-six thousand, seven hundred twenty-one".