18722817 has 12 divisors (see below), whose sum is σ = 27081600. Its totient is φ = 12464568.

The previous prime is 18722813. The next prime is 18722827. The reversal of 18722817 is 71822781.

It is a happy number.

It is not a de Polignac number, because 18722817 - 2² = 18722813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18722813) 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, 11848 + ... + 13334.

It is an arithmetic number, because the mean of its divisors is an integer number (2256800).

Almost surely, 2^18722817 is an apocalyptic number.

It is an amenable number.

18722817 is a deficient number, since it is larger than the sum of its proper divisors (8358783).

18722817 is a wasteful number, since it uses less digits than its factorization.

18722817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2892 (or 2889 counting only the distinct ones).

The product of its digits is 12544, while the sum is 36.

The square root of 18722817 is about 4326.9870579885. The cubic root of 18722817 is about 265.5361968800.

Subtracting from 18722817 its sum of digits (36), we obtain a palindrome (18722781).

The spelling of 18722817 in words is "eighteen million, seven hundred twenty-two thousand, eight hundred seventeen".