21908880 has 360 divisors, whose sum is σ = 92619072. Its totient is φ = 4790016.

The previous prime is 21908851. The next prime is 21908899. The reversal of 21908880 is 8880912.

It is a tau number, because it is divible by the number of its divisors (360).

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

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 71 ways as a sum of consecutive naturals, for example, 952549 + ... + 952571.

Almost surely, 2^21908880 is an apocalyptic number.

21908880 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 21908880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46309536).

21908880 is an abundant number, since it is smaller than the sum of its proper divisors (70710192).

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

21908880 is a wasteful number, since it uses less digits than its factorization.

21908880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65 (or 40 counting only the distinct ones).

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

The square root of 21908880 is about 4680.6922564937. The cubic root of 21908880 is about 279.8165464958.

The spelling of 21908880 in words is "twenty-one million, nine hundred eight thousand, eight hundred eighty".