13577316721 has 2 divisors, whose sum is σ = 13577316722. Its totient is φ = 13577316720.

The previous prime is 13577316671. The next prime is 13577316757. The reversal of 13577316721 is 12761377531.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13564096225 + 13220496 = 116465^2 + 3636^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13577316721 is a prime.

It is not a weakly prime, because it can be changed into another prime (13577316121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6788658360 + 6788658361.

It is an arithmetic number, because the mean of its divisors is an integer number (6788658361).

Almost surely, 2^13577316721 is an apocalyptic number.

It is an amenable number.

13577316721 is a deficient number, since it is larger than the sum of its proper divisors (1).

13577316721 is an equidigital number, since it uses as much as digits as its factorization.

13577316721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 185220, while the sum is 43.

The spelling of 13577316721 in words is "thirteen billion, five hundred seventy-seven million, three hundred sixteen thousand, seven hundred twenty-one".