18108981 has 48 divisors (see below), whose sum is σ = 30898560. Its totient is φ = 10454400.

The previous prime is 18108973. The next prime is 18108983. The reversal of 18108981 is 18980181.

It is not a de Polignac number, because 18108981 - 2³ = 18108973 is a prime.

It is a super-2 number, since 2×18108981² = 655870385716722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18108983) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 75021 + ... + 75261.

It is an arithmetic number, because the mean of its divisors is an integer number (643720).

Almost surely, 2^18108981 is an apocalyptic number.

18108981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18108981 is a deficient number, since it is larger than the sum of its proper divisors (12789579).

18108981 is a wasteful number, since it uses less digits than its factorization.

18108981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295 (or 278 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 36.

The square root of 18108981 is about 4255.4648394741. The cubic root of 18108981 is about 262.6019848621.

The spelling of 18108981 in words is "eighteen million, one hundred eight thousand, nine hundred eighty-one".