18245521 has 4 divisors (see below), whose sum is σ = 20852032. Its totient is φ = 15639012.

The previous prime is 18245503. The next prime is 18245581. The reversal of 18245521 is 12554281.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18245521 - 2⁵ = 18245489 is a prime.

It is a super-2 number, since 2×18245521² = 665798073122882, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18245521.

It is not an unprimeable number, because it can be changed into a prime (18245501) 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, 1303245 + ... + 1303258.

It is an arithmetic number, because the mean of its divisors is an integer number (5213008).

Almost surely, 2^18245521 is an apocalyptic number.

It is an amenable number.

18245521 is a deficient number, since it is larger than the sum of its proper divisors (2606511).

18245521 is an equidigital number, since it uses as much as digits as its factorization.

18245521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2606510.

The product of its digits is 3200, while the sum is 28.

The square root of 18245521 is about 4271.4776131920. The cubic root of 18245521 is about 263.2603310253.

The spelling of 18245521 in words is "eighteen million, two hundred forty-five thousand, five hundred twenty-one".