21888120 has 64 divisors (see below), whose sum is σ = 66096000. Its totient is φ = 5798528.

The previous prime is 21888109. The next prime is 21888121. The reversal of 21888120 is 2188812.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21888121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20971 + ... + 21989.

It is an arithmetic number, because the mean of its divisors is an integer number (1032750).

Almost surely, 2^21888120 is an apocalyptic number.

21888120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21888120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33048000).

21888120 is an abundant number, since it is smaller than the sum of its proper divisors (44207880).

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

21888120 is a wasteful number, since it uses less digits than its factorization.

21888120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1212 (or 1208 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 30.

The square root of 21888120 is about 4678.4741102201. The cubic root of 21888120 is about 279.7281374844.

The spelling of 21888120 in words is "twenty-one million, eight hundred eighty-eight thousand, one hundred twenty".