21185168 has 20 divisors (see below), whose sum is σ = 41178540. Its totient is φ = 10558464.

The previous prime is 21185123. The next prime is 21185173. The reversal of 21185168 is 86158112.

It can be written as a sum of positive squares in 2 ways, for example, as 4276624 + 16908544 = 2068^2 + 4112^2 .

It is a super-2 number, since 2×21185168² = 897622686376448, which contains 22 as substring.

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, 3428 + ... + 7356.

It is an arithmetic number, because the mean of its divisors is an integer number (2058927).

Almost surely, 2^21185168 is an apocalyptic number.

It is an amenable number.

21185168 is a deficient number, since it is larger than the sum of its proper divisors (19993372).

21185168 is a wasteful number, since it uses less digits than its factorization.

21185168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4274 (or 4268 counting only the distinct ones).

The product of its digits is 3840, while the sum is 32.

The square root of 21185168 is about 4602.7348392016. The cubic root of 21185168 is about 276.7009418674.

The spelling of 21185168 in words is "twenty-one million, one hundred eighty-five thousand, one hundred sixty-eight".