21857168 has 20 divisors (see below), whose sum is σ = 42437388. Its totient is φ = 10905600.

The previous prime is 21857161. The next prime is 21857179. The reversal of 21857168 is 86175812.

It can be written as a sum of positive squares in 2 ways, for example, as 18939904 + 2917264 = 4352^2 + 1708^2 .

It is not an unprimeable number, because it can be changed into a prime (21857161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8480 + ... + 10752.

Almost surely, 2^21857168 is an apocalyptic number.

It is an amenable number.

21857168 is a deficient number, since it is larger than the sum of its proper divisors (20580220).

21857168 is a wasteful number, since it uses less digits than its factorization.

21857168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2882 (or 2876 counting only the distinct ones).

The product of its digits is 26880, while the sum is 38.

The square root of 21857168 is about 4675.1650238254. The cubic root of 21857168 is about 279.5962207235.

The spelling of 21857168 in words is "twenty-one million, eight hundred fifty-seven thousand, one hundred sixty-eight".