21988800 has 168 divisors, whose sum is σ = 80314800. Its totient is φ = 5852160.

The previous prime is 21988793. The next prime is 21988801. The reversal of 21988800 is 888912.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21988801) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 42946 + ... + 43454.

Almost surely, 2^21988800 is an apocalyptic number.

21988800 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 21988800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40157400).

21988800 is an abundant number, since it is smaller than the sum of its proper divisors (58326000).

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

21988800 is a wasteful number, since it uses less digits than its factorization.

21988800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540 (or 519 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

The square root of 21988800 is about 4689.2216838192. The cubic root of 21988800 is about 280.1563752359.

The spelling of 21988800 in words is "twenty-one million, nine hundred eighty-eight thousand, eight hundred".