18220689 has 12 divisors (see below), whose sum is σ = 26356356. Its totient is φ = 12129792.

The previous prime is 18220679. The next prime is 18220693. The reversal of 18220689 is 98602281.

It can be written as a sum of positive squares in 2 ways, for example, as 14288400 + 3932289 = 3780^2 + 1983^2 .

It is not a de Polignac number, because 18220689 - 2⁷ = 18220561 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18220619) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9889 + ... + 11585.

It is an arithmetic number, because the mean of its divisors is an integer number (2196363).

Almost surely, 2^18220689 is an apocalyptic number.

It is an amenable number.

18220689 is a deficient number, since it is larger than the sum of its proper divisors (8135667).

18220689 is a wasteful number, since it uses less digits than its factorization.

18220689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2896 (or 2893 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 18220689 is about 4268.5699010324. The cubic root of 18220689 is about 263.1408451066.

The spelling of 18220689 in words is "eighteen million, two hundred twenty thousand, six hundred eighty-nine".