18161985 has 8 divisors (see below), whose sum is σ = 29059200. Its totient is φ = 9686384.

The previous prime is 18161981. The next prime is 18161993. The reversal of 18161985 is 58916181.

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

It is a cyclic number.

It is not a de Polignac number, because 18161985 - 2² = 18161981 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18161981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 605385 + ... + 605414.

It is an arithmetic number, because the mean of its divisors is an integer number (3632400).

Almost surely, 2^18161985 is an apocalyptic number.

18161985 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18161985 is a deficient number, since it is larger than the sum of its proper divisors (10897215).

18161985 is a wasteful number, since it uses less digits than its factorization.

18161985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1210807.

The product of its digits is 17280, while the sum is 39.

The square root of 18161985 is about 4261.6880458335. The cubic root of 18161985 is about 262.8579425301.

The spelling of 18161985 in words is "eighteen million, one hundred sixty-one thousand, nine hundred eighty-five".