21115968 has 56 divisors (see below), whose sum is σ = 56692800. Its totient is φ = 6935040.

The previous prime is 21115961. The next prime is 21115993. The reversal of 21115968 is 86951112.

It is not an unprimeable number, because it can be changed into a prime (21115961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12858 + ... + 14406.

Almost surely, 2^21115968 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21115968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28346400).

21115968 is an abundant number, since it is smaller than the sum of its proper divisors (35576832).

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

21115968 is a wasteful number, since it uses less digits than its factorization.

21115968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1635 (or 1625 counting only the distinct ones).

The product of its digits is 4320, while the sum is 33.

The square root of 21115968 is about 4595.2114205986. The cubic root of 21115968 is about 276.3993379127.

The spelling of 21115968 in words is "twenty-one million, one hundred fifteen thousand, nine hundred sixty-eight".