18981886 has 16 divisors (see below), whose sum is σ = 35498880. Its totient is φ = 7395480.

The previous prime is 18981881. The next prime is 18981887. The reversal of 18981886 is 68818981.

It is a super-2 number, since 2×18981886² = 720623992233992, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18981881) 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, 61476 + ... + 61783.

It is an arithmetic number, because the mean of its divisors is an integer number (2218680).

Almost surely, 2^18981886 is an apocalyptic number.

18981886 is a deficient number, since it is larger than the sum of its proper divisors (16516994).

18981886 is a wasteful number, since it uses less digits than its factorization.

18981886 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123279.

The product of its digits is 221184, while the sum is 49.

The square root of 18981886 is about 4356.8206297712. The cubic root of 18981886 is about 266.7553389141.

The spelling of 18981886 in words is "eighteen million, nine hundred eighty-one thousand, eight hundred eighty-six".