21617118 has 20 divisors (see below), whose sum is σ = 48438720. Its totient is φ = 7205652.

The previous prime is 21617111. The next prime is 21617143. The reversal of 21617118 is 81171612.

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

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21617091 and 21617100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21617111) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 66558 + ... + 66881.

It is an arithmetic number, because the mean of its divisors is an integer number (2421936).

Almost surely, 2^21617118 is an apocalyptic number.

21617118 is an abundant number, since it is smaller than the sum of its proper divisors (26821602).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21617118 is a wasteful number, since it uses less digits than its factorization.

21617118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133453 (or 133444 counting only the distinct ones).

The product of its digits is 672, while the sum is 27.

The square root of 21617118 is about 4649.4212543068. The cubic root of 21617118 is about 278.5688797738.

The spelling of 21617118 in words is "twenty-one million, six hundred seventeen thousand, one hundred eighteen".