21118688 has 48 divisors (see below), whose sum is σ = 43747200. Its totient is φ = 10022400.

The previous prime is 21118663. The next prime is 21118717. The reversal of 21118688 is 88681112.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 60338 + ... + 60686.

It is an arithmetic number, because the mean of its divisors is an integer number (911400).

Almost surely, 2^21118688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21118688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21873600).

21118688 is an abundant number, since it is smaller than the sum of its proper divisors (22628512).

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

21118688 is a wasteful number, since it uses less digits than its factorization.

21118688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451 (or 443 counting only the distinct ones).

The product of its digits is 6144, while the sum is 35.

The square root of 21118688 is about 4595.5073713356. The cubic root of 21118688 is about 276.4112052970.

The spelling of 21118688 in words is "twenty-one million, one hundred eighteen thousand, six hundred eighty-eight".