21727228 has 6 divisors (see below), whose sum is σ = 38022656. Its totient is φ = 10863612.

The previous prime is 21727217. The next prime is 21727231. The reversal of 21727228 is 82272712.

It is a self number, because there is not a number n which added to its sum of digits gives 21727228.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2715900 + ... + 2715907.

Almost surely, 2^21727228 is an apocalyptic number.

It is an amenable number.

21727228 is a deficient number, since it is larger than the sum of its proper divisors (16295428).

21727228 is a wasteful number, since it uses less digits than its factorization.

21727228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5431811 (or 5431809 counting only the distinct ones).

The product of its digits is 6272, while the sum is 31.

The square root of 21727228 is about 4661.2474725121. The cubic root of 21727228 is about 279.0410562945.

The spelling of 21727228 in words is "twenty-one million, seven hundred twenty-seven thousand, two hundred twenty-eight".