21828772 has 12 divisors (see below), whose sum is σ = 43657600. Its totient is φ = 9355176.

The previous prime is 21828767. The next prime is 21828791. The reversal of 21828772 is 27782812.

It is a happy number.

21828772 is an admirable 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, 389772 + ... + 389827.

Almost surely, 2^21828772 is an apocalyptic number.

It is an amenable number.

21828772 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21828772 is a wasteful number, since it uses less digits than its factorization.

21828772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 779610 (or 779608 counting only the distinct ones).

The product of its digits is 25088, while the sum is 37.

The square root of 21828772 is about 4672.1271386811. The cubic root of 21828772 is about 279.4750879985.

The spelling of 21828772 in words is "twenty-one million, eight hundred twenty-eight thousand, seven hundred seventy-two".