18516081 has 16 divisors (see below), whose sum is σ = 25948800. Its totient is φ = 11721600.

The previous prime is 18516059. The next prime is 18516097. The reversal of 18516081 is 18061581.

It is a happy number.

It is not a de Polignac number, because 18516081 - 2⁵ = 18516049 is a prime.

It is a super-2 number, since 2×18516081² = 685690511197122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18516031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9381 + ... + 11181.

It is an arithmetic number, because the mean of its divisors is an integer number (1621800).

Almost surely, 2^18516081 is an apocalyptic number.

It is an amenable number.

18516081 is a deficient number, since it is larger than the sum of its proper divisors (7432719).

18516081 is a wasteful number, since it uses less digits than its factorization.

18516081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1976.

The product of its (nonzero) digits is 1920, while the sum is 30.

The square root of 18516081 is about 4303.0316057403. The cubic root of 18516081 is about 264.5552335270. Note that the first 3 decimals are identical.

The spelling of 18516081 in words is "eighteen million, five hundred sixteen thousand, eighty-one".