18091986 has 16 divisors (see below), whose sum is σ = 39473568. Its totient is φ = 5482400.

The previous prime is 18091979. The next prime is 18091991. The reversal of 18091986 is 68919081.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 136995 + ... + 137126.

It is an arithmetic number, because the mean of its divisors is an integer number (2467098).

Almost surely, 2^18091986 is an apocalyptic number.

18091986 is an abundant number, since it is smaller than the sum of its proper divisors (21381582).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18091986 is a wasteful number, since it uses less digits than its factorization.

18091986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274137.

The product of its (nonzero) digits is 31104, while the sum is 42.

The square root of 18091986 is about 4253.4675266187. The cubic root of 18091986 is about 262.5198098429.

The spelling of 18091986 in words is "eighteen million, ninety-one thousand, nine hundred eighty-six".