21854866 has 16 divisors (see below), whose sum is σ = 35834400. Its totient is φ = 9914080.

The previous prime is 21854837. The next prime is 21854867. The reversal of 21854866 is 66845812.

It is not an unprimeable number, because it can be changed into a prime (21854867) 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, 20310 + ... + 21358.

It is an arithmetic number, because the mean of its divisors is an integer number (2239650).

Almost surely, 2^21854866 is an apocalyptic number.

21854866 is a deficient number, since it is larger than the sum of its proper divisors (13979534).

21854866 is a wasteful number, since it uses less digits than its factorization.

21854866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2009.

The product of its digits is 92160, while the sum is 40.

The square root of 21854866 is about 4674.9188228246. The cubic root of 21854866 is about 279.5864046745.

The spelling of 21854866 in words is "twenty-one million, eight hundred fifty-four thousand, eight hundred sixty-six".