18081566 has 8 divisors (see below), whose sum is σ = 27179064. Its totient is φ = 9021880.

The previous prime is 18081563. The next prime is 18081593. The reversal of 18081566 is 66518081.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18081563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8225 + ... + 10188.

It is an arithmetic number, because the mean of its divisors is an integer number (3397383).

Almost surely, 2^18081566 is an apocalyptic number.

18081566 is a deficient number, since it is larger than the sum of its proper divisors (9097498).

18081566 is a wasteful number, since it uses less digits than its factorization.

18081566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18906.

The product of its (nonzero) digits is 11520, while the sum is 35.

The square root of 18081566 is about 4252.2424672166. The cubic root of 18081566 is about 262.4694011196.

The spelling of 18081566 in words is "eighteen million, eighty-one thousand, five hundred sixty-six".