18638081 has 24 divisors (see below), whose sum is σ = 23912640. Its totient is φ = 14364000.

The previous prime is 18638071. The next prime is 18638089. The reversal of 18638081 is 18083681.

It is a happy number.

It is not a de Polignac number, because 18638081 - 2¹⁰ = 18637057 is a prime.

It is a super-2 number, since 2×18638081² = 694756126725122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18638089) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 81275 + ... + 81503.

It is an arithmetic number, because the mean of its divisors is an integer number (996360).

Almost surely, 2^18638081 is an apocalyptic number.

18638081 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18638081 is a deficient number, since it is larger than the sum of its proper divisors (5274559).

18638081 is a wasteful number, since it uses less digits than its factorization.

18638081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405 (or 398 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 35.

The square root of 18638081 is about 4317.1843833684. The cubic root of 18638081 is about 265.1350018193.

The spelling of 18638081 in words is "eighteen million, six hundred thirty-eight thousand, eighty-one".