21521168 has 20 divisors (see below), whose sum is σ = 41790480. Its totient is φ = 10736544.

The previous prime is 21521141. The next prime is 21521183. The reversal of 21521168 is 86112512.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7523 + ... + 9981.

It is an arithmetic number, because the mean of its divisors is an integer number (2089524).

Almost surely, 2^21521168 is an apocalyptic number.

It is an amenable number.

21521168 is a deficient number, since it is larger than the sum of its proper divisors (20269312).

21521168 is a wasteful number, since it uses less digits than its factorization.

21521168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3014 (or 3008 counting only the distinct ones).

The product of its digits is 960, while the sum is 26.

The square root of 21521168 is about 4639.0912903283. The cubic root of 21521168 is about 278.1561154095.

The spelling of 21521168 in words is "twenty-one million, five hundred twenty-one thousand, one hundred sixty-eight".