21855668 has 12 divisors (see below), whose sum is σ = 38818752. Its totient is φ = 10764600.

The previous prime is 21855649. The next prime is 21855671. The reversal of 21855668 is 86655812.

It is a congruent number.

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, 40508 + ... + 41043.

It is an arithmetic number, because the mean of its divisors is an integer number (3234896).

Almost surely, 2^21855668 is an apocalyptic number.

It is an amenable number.

21855668 is a deficient number, since it is larger than the sum of its proper divisors (16963084).

21855668 is a wasteful number, since it uses less digits than its factorization.

21855668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81622 (or 81620 counting only the distinct ones).

The product of its digits is 115200, while the sum is 41.

The square root of 21855668 is about 4675.0045989282. The cubic root of 21855668 is about 279.5898245925.

The spelling of 21855668 in words is "twenty-one million, eight hundred fifty-five thousand, six hundred sixty-eight".