13165561 has 2 divisors, whose sum is σ = 13165562. Its totient is φ = 13165560.

The previous prime is 13165541. The next prime is 13165573. The reversal of 13165561 is 16556131.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12075625 + 1089936 = 3475^2 + 1044^2 .

It is a cyclic number.

It is not a de Polignac number, because 13165561 - 2²³ = 4776953 is a prime.

It is not a weakly prime, because it can be changed into another prime (13165501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6582780 + 6582781.

It is an arithmetic number, because the mean of its divisors is an integer number (6582781).

Almost surely, 2^13165561 is an apocalyptic number.

It is an amenable number.

13165561 is a deficient number, since it is larger than the sum of its proper divisors (1).

13165561 is an equidigital number, since it uses as much as digits as its factorization.

13165561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2700, while the sum is 28.

The square root of 13165561 is about 3628.4378181250. The cubic root of 13165561 is about 236.1274388319.

The spelling of 13165561 in words is "thirteen million, one hundred sixty-five thousand, five hundred sixty-one".