18172731166 has 4 divisors (see below), whose sum is σ = 27259096752. Its totient is φ = 9086365582.

The previous prime is 18172731151. The next prime is 18172731167. The reversal of 18172731166 is 66113727181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66113727181 = 14489 ⋅4563029.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18172731167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4543182790 + ... + 4543182793.

It is an arithmetic number, because the mean of its divisors is an integer number (6814774188).

Almost surely, 2^18172731166 is an apocalyptic number.

18172731166 is a deficient number, since it is larger than the sum of its proper divisors (9086365586).

18172731166 is an equidigital number, since it uses as much as digits as its factorization.

18172731166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9086365585.

The product of its digits is 84672, while the sum is 43.

The spelling of 18172731166 in words is "eighteen billion, one hundred seventy-two million, seven hundred thirty-one thousand, one hundred sixty-six".