21816960 has 128 divisors (see below), whose sum is σ = 75936960. Its totient is φ = 5283840.

The previous prime is 21816941. The next prime is 21817021. The reversal of 21816960 is 6961812.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (33).

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, 20604 + ... + 21636.

Almost surely, 2^21816960 is an apocalyptic number.

21816960 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 21816960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37968480).

21816960 is an abundant number, since it is smaller than the sum of its proper divisors (54120000).

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

21816960 is a wasteful number, since it uses less digits than its factorization.

21816960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1066 (or 1054 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 21816960 is about 4670.8628753154. The cubic root of 21816960 is about 279.4246689863.

The spelling of 21816960 in words is "twenty-one million, eight hundred sixteen thousand, nine hundred sixty".