21942228 has 48 divisors (see below), whose sum is σ = 63834624. Its totient is φ = 5699040.

The previous prime is 21942209. The next prime is 21942251. The reversal of 21942228 is 82224912.

It is a super-2 number, since 2×21942228² = 962922739207968, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21942195 and 21942204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10950 + ... + 12797.

It is an arithmetic number, because the mean of its divisors is an integer number (1329888).

Almost surely, 2^21942228 is an apocalyptic number.

21942228 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21942228 is an abundant number, since it is smaller than the sum of its proper divisors (41892396).

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

21942228 is a wasteful number, since it uses less digits than its factorization.

21942228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23772 (or 23770 counting only the distinct ones).

The product of its digits is 4608, while the sum is 30.

The square root of 21942228 is about 4684.2531955478. The cubic root of 21942228 is about 279.9584462144.

It can be divided in two parts, 21 and 942228, that added together give a palindrome (942249).

The spelling of 21942228 in words is "twenty-one million, nine hundred forty-two thousand, two hundred twenty-eight".