21216960 has 168 divisors, whose sum is σ = 74889360. Its totient is φ = 5511168.

The previous prime is 21216941. The next prime is 21216961. The reversal of 21216960 is 6961212.

It is not an unprimeable number, because it can be changed into a prime (21216961) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 152571 + ... + 152709.

It is an arithmetic number, because the mean of its divisors is an integer number (445770).

Almost surely, 2^21216960 is an apocalyptic number.

21216960 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 21216960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37444680).

21216960 is an abundant number, since it is smaller than the sum of its proper divisors (53672400).

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

21216960 is a wasteful number, since it uses less digits than its factorization.

21216960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215 (or 202 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 21216960 is about 4606.1871433975. The cubic root of 21216960 is about 276.8392851901.

The spelling of 21216960 in words is "twenty-one million, two hundred sixteen thousand, nine hundred sixty".