21866894 has 16 divisors (see below), whose sum is σ = 37647456. Its totient is φ = 9331200.

The previous prime is 21866893. The next prime is 21866903. The reversal of 21866894 is 49866812.

It is a happy number.

It is a super-2 number, since 2×21866894² = 956322106414472, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21866893) 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 7 ways as a sum of consecutive naturals, for example, 134 + ... + 6614.

It is an arithmetic number, because the mean of its divisors is an integer number (2352966).

Almost surely, 2^21866894 is an apocalyptic number.

21866894 is a deficient number, since it is larger than the sum of its proper divisors (15780562).

21866894 is a wasteful number, since it uses less digits than its factorization.

21866894 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6731.

The product of its digits is 165888, while the sum is 44.

The square root of 21866894 is about 4676.2050853229. The cubic root of 21866894 is about 279.6376861379.

The spelling of 21866894 in words is "twenty-one million, eight hundred sixty-six thousand, eight hundred ninety-four".