21142228 has 12 divisors (see below), whose sum is σ = 37104480. Its totient is φ = 10540952.

The previous prime is 21142223. The next prime is 21142243. The reversal of 21142228 is 82224112.

It is a junction number, because it is equal to n+sod(n) for n = 21142199 and 21142208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142223) 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 3 ways as a sum of consecutive naturals, for example, 5926 + ... + 8797.

It is an arithmetic number, because the mean of its divisors is an integer number (3092040).

Almost surely, 2^21142228 is an apocalyptic number.

It is an amenable number.

21142228 is a deficient number, since it is larger than the sum of its proper divisors (15962252).

21142228 is a wasteful number, since it uses less digits than its factorization.

21142228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15086 (or 15084 counting only the distinct ones).

The product of its digits is 512, while the sum is 22.

The square root of 21142228 is about 4598.0678550887. The cubic root of 21142228 is about 276.5138679828.

The spelling of 21142228 in words is "twenty-one million, one hundred forty-two thousand, two hundred twenty-eight".