18173123665 has 16 divisors (see below), whose sum is σ = 21870007056. Its totient is φ = 14497056000.

The previous prime is 18173123587. The next prime is 18173123681. The reversal of 18173123665 is 56632137181.

It can be written as a sum of positive squares in 8 ways, for example, as 1749163329 + 16423960336 = 41823^2 + 128156^2 .

It is not a de Polignac number, because 18173123665 - 2¹⁹ = 18172599377 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2881015 + ... + 2887315.

It is an arithmetic number, because the mean of its divisors is an integer number (1366875441).

Almost surely, 2^18173123665 is an apocalyptic number.

It is an amenable number.

18173123665 is a deficient number, since it is larger than the sum of its proper divisors (3696883391).

18173123665 is an equidigital number, since it uses as much as digits as its factorization.

18173123665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7860.

The product of its digits is 181440, while the sum is 43.

The spelling of 18173123665 in words is "eighteen billion, one hundred seventy-three million, one hundred twenty-three thousand, six hundred sixty-five".