21866986 has 16 divisors (see below), whose sum is σ = 35719200. Its totient is φ = 10000368.

The previous prime is 21866941. The next prime is 21866989. The reversal of 21866986 is 68966812.

It is not an unprimeable number, because it can be changed into a prime (21866989) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8820 + ... + 11023.

It is an arithmetic number, because the mean of its divisors is an integer number (2232450).

Almost surely, 2^21866986 is an apocalyptic number.

21866986 is a deficient number, since it is larger than the sum of its proper divisors (13852214).

21866986 is a wasteful number, since it uses less digits than its factorization.

21866986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19893.

The product of its digits is 248832, while the sum is 46.

The square root of 21866986 is about 4676.2149223491. The cubic root of 21866986 is about 279.6380783081.

The spelling of 21866986 in words is "twenty-one million, eight hundred sixty-six thousand, nine hundred eighty-six".