21185868 has 24 divisors (see below), whose sum is σ = 53928000. Its totient is φ = 6419920.

The previous prime is 21185839. The next prime is 21185873. The reversal of 21185868 is 86858112.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80118 + ... + 80381.

It is an arithmetic number, because the mean of its divisors is an integer number (2247000).

Almost surely, 2^21185868 is an apocalyptic number.

It is an amenable number.

21185868 is an abundant number, since it is smaller than the sum of its proper divisors (32742132).

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

21185868 is a wasteful number, since it uses less digits than its factorization.

21185868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160517 (or 160515 counting only the distinct ones).

The product of its digits is 30720, while the sum is 39.

The square root of 21185868 is about 4602.8108803209. The cubic root of 21185868 is about 276.7039894166.

The spelling of 21185868 in words is "twenty-one million, one hundred eighty-five thousand, eight hundred sixty-eight".