18265521 has 16 divisors (see below), whose sum is σ = 24772608. Its totient is φ = 11970000.

The previous prime is 18265501. The next prime is 18265543. The reversal of 18265521 is 12556281.

It is not a de Polignac number, because 18265521 - 2⁷ = 18265393 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18265501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 72646 + ... + 72896.

It is an arithmetic number, because the mean of its divisors is an integer number (1548288).

Almost surely, 2^18265521 is an apocalyptic number.

It is an amenable number.

18265521 is a deficient number, since it is larger than the sum of its proper divisors (6507087).

18265521 is a wasteful number, since it uses less digits than its factorization.

18265521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 572.

The product of its digits is 4800, while the sum is 30.

The square root of 18265521 is about 4273.8180822305. The cubic root of 18265521 is about 263.3564876648.

It can be divided in two parts, 182 and 65521, that added together give a triangular number (65703 = T₃₆₂).

The spelling of 18265521 in words is "eighteen million, two hundred sixty-five thousand, five hundred twenty-one".