18031521 has 8 divisors (see below), whose sum is σ = 24449760. Its totient is φ = 11817152.

The previous prime is 18031483. The next prime is 18031547. The reversal of 18031521 is 12513081.

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

It is a cyclic number.

It is not a de Polignac number, because 18031521 - 2⁶ = 18031457 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18031561) 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, 50760 + ... + 51113.

It is an arithmetic number, because the mean of its divisors is an integer number (3056220).

Almost surely, 2^18031521 is an apocalyptic number.

It is an amenable number.

18031521 is a deficient number, since it is larger than the sum of its proper divisors (6418239).

18031521 is a wasteful number, since it uses less digits than its factorization.

18031521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101935.

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 18031521 is about 4246.3538477145. The cubic root of 18031521 is about 262.2270287098.

The spelling of 18031521 in words is "eighteen million, thirty-one thousand, five hundred twenty-one".