18169997 has 4 divisors (see below), whose sum is σ = 18661116. Its totient is φ = 17678880.

The previous prime is 18169967. The next prime is 18170027. The reversal of 18169997 is 79996181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79996181 = 29 ⋅2758489.

It is an interprime number because it is at equal distance from previous prime (18169967) and next prime (18170027).

It can be written as a sum of positive squares in 2 ways, for example, as 6295081 + 11874916 = 2509^2 + 3446^2 .

It is a cyclic number.

It is not a de Polignac number, because 18169997 - 2¹⁶ = 18104461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18169927) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245504 + ... + 245577.

It is an arithmetic number, because the mean of its divisors is an integer number (4665279).

Almost surely, 2^18169997 is an apocalyptic number.

It is an amenable number.

18169997 is a deficient number, since it is larger than the sum of its proper divisors (491119).

18169997 is an equidigital number, since it uses as much as digits as its factorization.

18169997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491118.

The product of its digits is 244944, while the sum is 50.

The square root of 18169997 is about 4262.6279452938. The cubic root of 18169997 is about 262.8965893378.

The spelling of 18169997 in words is "eighteen million, one hundred sixty-nine thousand, nine hundred ninety-seven".