18561615073 has 2 divisors, whose sum is σ = 18561615074. Its totient is φ = 18561615072.

The previous prime is 18561615047. The next prime is 18561615131. The reversal of 18561615073 is 37051616581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17532937744 + 1028677329 = 132412^2 + 32073^2 .

It is a cyclic number.

It is not a de Polignac number, because 18561615073 - 2⁵ = 18561615041 is a prime.

It is not a weakly prime, because it can be changed into another prime (18561615473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9280807536 + 9280807537.

It is an arithmetic number, because the mean of its divisors is an integer number (9280807537).

Almost surely, 2^18561615073 is an apocalyptic number.

It is an amenable number.

18561615073 is a deficient number, since it is larger than the sum of its proper divisors (1).

18561615073 is an equidigital number, since it uses as much as digits as its factorization.

18561615073 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 151200, while the sum is 43.

The spelling of 18561615073 in words is "eighteen billion, five hundred sixty-one million, six hundred fifteen thousand, seventy-three".