21808068 has 24 divisors (see below), whose sum is σ = 51000768. Its totient is φ = 7252896.

The previous prime is 21808051. The next prime is 21808081. The reversal of 21808068 is 86080812.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4230 + ... + 7842.

It is an arithmetic number, because the mean of its divisors is an integer number (2125032).

Almost surely, 2^21808068 is an apocalyptic number.

It is an amenable number.

21808068 is an abundant number, since it is smaller than the sum of its proper divisors (29192700).

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

21808068 is a wasteful number, since it uses less digits than its factorization.

21808068 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4123 (or 4121 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 33.

The square root of 21808068 is about 4669.9109199213. The cubic root of 21808068 is about 279.3867018606.

The spelling of 21808068 in words is "twenty-one million, eight hundred eight thousand, sixty-eight".