18105815617 has 2 divisors, whose sum is σ = 18105815618. Its totient is φ = 18105815616.

The previous prime is 18105815603. The next prime is 18105815627. The reversal of 18105815617 is 71651850181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13950208321 + 4155607296 = 118111^2 + 64464^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18105815617 is a prime.

It is not a weakly prime, because it can be changed into another prime (18105815627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9052907808 + 9052907809.

It is an arithmetic number, because the mean of its divisors is an integer number (9052907809).

Almost surely, 2^18105815617 is an apocalyptic number.

It is an amenable number.

18105815617 is a deficient number, since it is larger than the sum of its proper divisors (1).

18105815617 is an equidigital number, since it uses as much as digits as its factorization.

18105815617 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 67200, while the sum is 43.

The spelling of 18105815617 in words is "eighteen billion, one hundred five million, eight hundred fifteen thousand, six hundred seventeen".