18165985 has 8 divisors (see below), whose sum is σ = 21865896. Its totient is φ = 14488320.

The previous prime is 18165967. The next prime is 18165991. The reversal of 18165985 is 58956181.

It can be written as a sum of positive squares in 4 ways, for example, as 154449 + 18011536 = 393^2 + 4244^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18165985 - 2¹⁵ = 18133217 is a prime.

It is a super-2 number, since 2×18165985² = 660006022040450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3706 + ... + 7075.

It is an arithmetic number, because the mean of its divisors is an integer number (2733237).

Almost surely, 2^18165985 is an apocalyptic number.

It is an amenable number.

18165985 is a deficient number, since it is larger than the sum of its proper divisors (3699911).

18165985 is a wasteful number, since it uses less digits than its factorization.

18165985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11123.

The product of its digits is 86400, while the sum is 43.

The square root of 18165985 is about 4262.1573176034. The cubic root of 18165985 is about 262.8772384127.

It can be divided in two parts, 181 and 65985, that added together give a palindrome (66166).

The spelling of 18165985 in words is "eighteen million, one hundred sixty-five thousand, nine hundred eighty-five".