21156960 has 96 divisors (see below), whose sum is σ = 72721152. Its totient is φ = 5127680.

The previous prime is 21156953. The next prime is 21157039. The reversal of 21156960 is 6965112.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

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, 3277 + ... + 7283.

It is an arithmetic number, because the mean of its divisors is an integer number (757512).

Almost surely, 2^21156960 is an apocalyptic number.

21156960 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 21156960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36360576).

21156960 is an abundant number, since it is smaller than the sum of its proper divisors (51564192).

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

21156960 is a wasteful number, since it uses less digits than its factorization.

21156960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4036 (or 4028 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 21156960 is about 4599.6695533484. The cubic root of 21156960 is about 276.5780784419.

The spelling of 21156960 in words is "twenty-one million, one hundred fifty-six thousand, nine hundred sixty".