21668885 has 8 divisors (see below), whose sum is σ = 29717376. Its totient is φ = 14858640.

The previous prime is 21668851. The next prime is 21668917. The reversal of 21668885 is 58886612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21668885 - 2⁸ = 21668629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 309521 + ... + 309590.

It is an arithmetic number, because the mean of its divisors is an integer number (3714672).

Almost surely, 2^21668885 is an apocalyptic number.

It is an amenable number.

21668885 is a deficient number, since it is larger than the sum of its proper divisors (8048491).

21668885 is an equidigital number, since it uses as much as digits as its factorization.

21668885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 619123.

The product of its digits is 184320, while the sum is 44.

The square root of 21668885 is about 4654.9849623817. The cubic root of 21668885 is about 278.7910675683.

The spelling of 21668885 in words is "twenty-one million, six hundred sixty-eight thousand, eight hundred eighty-five".