21818168 has 32 divisors (see below), whose sum is σ = 42940800. Its totient is φ = 10373088.

The previous prime is 21818149. The next prime is 21818171. The reversal of 21818168 is 86181812.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51863 + ... + 52281.

It is an arithmetic number, because the mean of its divisors is an integer number (1341900).

Almost surely, 2^21818168 is an apocalyptic number.

It is an amenable number.

21818168 is a deficient number, since it is larger than the sum of its proper divisors (21122632).

21818168 is a wasteful number, since it uses less digits than its factorization.

21818168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 731 (or 727 counting only the distinct ones).

The product of its digits is 6144, while the sum is 35.

The square root of 21818168 is about 4670.9921858209. The cubic root of 21818168 is about 279.4298261175.

The spelling of 21818168 in words is "twenty-one million, eight hundred eighteen thousand, one hundred sixty-eight".