18631044416561 has 2 divisors, whose sum is σ = 18631044416562. Its totient is φ = 18631044416560.

The previous prime is 18631044416483. The next prime is 18631044416599. The reversal of 18631044416561 is 16561444013681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17508207486961 + 1122836929600 = 4184281^2 + 1059640^2 .

It is a cyclic number.

It is not a de Polignac number, because 18631044416561 - 2³⁰ = 18629970674737 is a prime.

It is not a weakly prime, because it can be changed into another prime (18631044416261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9315522208280 + 9315522208281.

It is an arithmetic number, because the mean of its divisors is an integer number (9315522208281).

Almost surely, 2^{18631044416561} is an apocalyptic number.

It is an amenable number.

18631044416561 is a deficient number, since it is larger than the sum of its proper divisors (1).

18631044416561 is an equidigital number, since it uses as much as digits as its factorization.

18631044416561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1658880, while the sum is 50.

The spelling of 18631044416561 in words is "eighteen trillion, six hundred thirty-one billion, forty-four million, four hundred sixteen thousand, five hundred sixty-one".