21821168 has 20 divisors (see below), whose sum is σ = 42692208. Its totient is φ = 10803840.

The previous prime is 21821153. The next prime is 21821171. The reversal of 21821168 is 86112812.

It is a self number, because there is not a number n which added to its sum of digits gives 21821168.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4973 + ... + 8268.

Almost surely, 2^21821168 is an apocalyptic number.

It is an amenable number.

21821168 is a deficient number, since it is larger than the sum of its proper divisors (20871040).

21821168 is a wasteful number, since it uses less digits than its factorization.

21821168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13352 (or 13346 counting only the distinct ones).

The product of its digits is 1536, while the sum is 29.

The square root of 21821168 is about 4671.3133056989. The cubic root of 21821168 is about 279.4426327390.

The spelling of 21821168 in words is "twenty-one million, eight hundred twenty-one thousand, one hundred sixty-eight".