21608880 has 80 divisors (see below), whose sum is σ = 67495680. Its totient is φ = 5718784.

The previous prime is 21608837. The next prime is 21608893. The reversal of 21608880 is 8880612.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42709 + ... + 43211.

It is an arithmetic number, because the mean of its divisors is an integer number (843696).

Almost surely, 2^21608880 is an apocalyptic number.

21608880 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 21608880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33747840).

21608880 is an abundant number, since it is smaller than the sum of its proper divisors (45886800).

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

21608880 is a wasteful number, since it uses less digits than its factorization.

21608880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 698 (or 692 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 33.

The square root of 21608880 is about 4648.5352531738. The cubic root of 21608880 is about 278.5334889629.

The spelling of 21608880 in words is "twenty-one million, six hundred eight thousand, eight hundred eighty".