18086521 has 4 divisors (see below), whose sum is σ = 19150452. Its totient is φ = 17022592.

The previous prime is 18086507. The next prime is 18086539. The reversal of 18086521 is 12568081.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11634921 + 6451600 = 3411^2 + 2540^2 .

It is a cyclic number.

It is not a de Polignac number, because 18086521 - 2⁹ = 18086009 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18086021) 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, 531940 + ... + 531973.

It is an arithmetic number, because the mean of its divisors is an integer number (4787613).

Almost surely, 2^18086521 is an apocalyptic number.

It is an amenable number.

18086521 is a deficient number, since it is larger than the sum of its proper divisors (1063931).

18086521 is a wasteful number, since it uses less digits than its factorization.

18086521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1063930.

The product of its (nonzero) digits is 3840, while the sum is 31.

The square root of 18086521 is about 4252.8250610624. The cubic root of 18086521 is about 262.4933742848.

The spelling of 18086521 in words is "eighteen million, eighty-six thousand, five hundred twenty-one".