21153228 has 24 divisors (see below), whose sum is σ = 49454832. Its totient is φ = 7037184.

The previous prime is 21153227. The next prime is 21153257. The reversal of 21153228 is 82235112.

It is a junction number, because it is equal to n+sod(n) for n = 21153198 and 21153207.

It is not an unprimeable number, because it can be changed into a prime (21153227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5976 + ... + 8832.

It is an arithmetic number, because the mean of its divisors is an integer number (2060618).

Almost surely, 2^21153228 is an apocalyptic number.

It is an amenable number.

21153228 is an abundant number, since it is smaller than the sum of its proper divisors (28301604).

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

21153228 is a wasteful number, since it uses less digits than its factorization.

21153228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3481 (or 3479 counting only the distinct ones).

The product of its digits is 960, while the sum is 24.

The square root of 21153228 is about 4599.2638541401. The cubic root of 21153228 is about 276.5618150770.

The spelling of 21153228 in words is "twenty-one million, one hundred fifty-three thousand, two hundred twenty-eight".