21228332 has 6 divisors (see below), whose sum is σ = 37149588. Its totient is φ = 10614164.

The previous prime is 21228331. The next prime is 21228341. The reversal of 21228332 is 23382212.

It is a junction number, because it is equal to n+sod(n) for n = 21228298 and 21228307.

It is not an unprimeable number, because it can be changed into a prime (21228331) 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 as a sum of consecutive naturals, namely, 2653538 + ... + 2653545.

It is an arithmetic number, because the mean of its divisors is an integer number (6191598).

Almost surely, 2^21228332 is an apocalyptic number.

It is an amenable number.

21228332 is a deficient number, since it is larger than the sum of its proper divisors (15921256).

21228332 is a wasteful number, since it uses less digits than its factorization.

21228332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5307087 (or 5307085 counting only the distinct ones).

The product of its digits is 1152, while the sum is 23.

The square root of 21228332 is about 4607.4214046471. The cubic root of 21228332 is about 276.8887370445. Note that the first 3 decimals are identical.

The spelling of 21228332 in words is "twenty-one million, two hundred twenty-eight thousand, three hundred thirty-two".