21974228 has 12 divisors (see below), whose sum is σ = 39781140. Its totient is φ = 10608192.

The previous prime is 21974201. The next prime is 21974243. The reversal of 21974228 is 82247912.

It can be written as a sum of positive squares in 2 ways, for example, as 16875664 + 5098564 = 4108^2 + 2258^2 .

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 94601 + ... + 94832.

It is an arithmetic number, because the mean of its divisors is an integer number (3315095).

Almost surely, 2^21974228 is an apocalyptic number.

It is an amenable number.

21974228 is a deficient number, since it is larger than the sum of its proper divisors (17806912).

21974228 is a wasteful number, since it uses less digits than its factorization.

21974228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189466 (or 189464 counting only the distinct ones).

The product of its digits is 16128, while the sum is 35.

The square root of 21974228 is about 4687.6676503353. The cubic root of 21974228 is about 280.0944749223.

It can be divided in two parts, 219 and 74228, that added together give a palindrome (74447).

The spelling of 21974228 in words is "twenty-one million, nine hundred seventy-four thousand, two hundred twenty-eight".