18028521 has 24 divisors (see below), whose sum is σ = 31071840. Its totient is φ = 10301256.

The previous prime is 18028519. The next prime is 18028523. The reversal of 18028521 is 12582081.

It is an interprime number because it is at equal distance from previous prime (18028519) and next prime (18028523).

It is not a de Polignac number, because 18028521 - 2¹ = 18028519 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (18028523) 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 23 ways as a sum of consecutive naturals, for example, 5491 + ... + 8136.

It is an arithmetic number, because the mean of its divisors is an integer number (1294660).

Almost surely, 2^18028521 is an apocalyptic number.

It is an amenable number.

18028521 is a deficient number, since it is larger than the sum of its proper divisors (13043319).

18028521 is a wasteful number, since it uses less digits than its factorization.

18028521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13650 (or 13637 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 27.

The square root of 18028521 is about 4246.0005887894. Note that the first 3 decimals coincide. The cubic root of 18028521 is about 262.2124852016.

The spelling of 18028521 in words is "eighteen million, twenty-eight thousand, five hundred twenty-one".