21306866 has 24 divisors (see below), whose sum is σ = 39138480. Its totient is φ = 8650152.

The previous prime is 21306823. The next prime is 21306869. The reversal of 21306866 is 66860312.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21306869) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 3860 + ... + 7583.

It is an arithmetic number, because the mean of its divisors is an integer number (1630770).

Almost surely, 2^21306866 is an apocalyptic number.

21306866 is a deficient number, since it is larger than the sum of its proper divisors (17831614).

21306866 is a wasteful number, since it uses less digits than its factorization.

21306866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11478 (or 11471 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 21306866 is about 4615.9360914120. The cubic root of 21306866 is about 277.2297658748.

The spelling of 21306866 in words is "twenty-one million, three hundred six thousand, eight hundred sixty-six".