18215489 has 4 divisors (see below), whose sum is σ = 18228420. Its totient is φ = 18202560.

The previous prime is 18215473. The next prime is 18215497. The reversal of 18215489 is 98451281.

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 10291264 + 7924225 = 3208^2 + 2815^2 .

It is a cyclic number.

It is not a de Polignac number, because 18215489 - 2⁴ = 18215473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18215189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4052 + ... + 7269.

It is an arithmetic number, because the mean of its divisors is an integer number (4557105).

Almost surely, 2^18215489 is an apocalyptic number.

It is an amenable number.

18215489 is a deficient number, since it is larger than the sum of its proper divisors (12931).

18215489 is a wasteful number, since it uses less digits than its factorization.

18215489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12930.

The product of its digits is 23040, while the sum is 38.

The square root of 18215489 is about 4267.9607542713. The cubic root of 18215489 is about 263.1158101480.

The spelling of 18215489 in words is "eighteen million, two hundred fifteen thousand, four hundred eighty-nine".