21466921 has 16 divisors (see below), whose sum is σ = 25436160. Its totient is φ = 17735760.

The previous prime is 21466909. The next prime is 21466957. The reversal of 21466921 is 12966412.

It is not a de Polignac number, because 21466921 - 2¹⁷ = 21335849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21466901) 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 15 ways as a sum of consecutive naturals, for example, 22900 + ... + 23818.

It is an arithmetic number, because the mean of its divisors is an integer number (1589760).

Almost surely, 2^21466921 is an apocalyptic number.

It is an amenable number.

21466921 is a deficient number, since it is larger than the sum of its proper divisors (3969239).

21466921 is an equidigital number, since it uses as much as digits as its factorization.

21466921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1044.

The product of its digits is 5184, while the sum is 31.

The square root of 21466921 is about 4633.2408743772. The cubic root of 21466921 is about 277.9222087950.

The spelling of 21466921 in words is "twenty-one million, four hundred sixty-six thousand, nine hundred twenty-one".