21943228 has 6 divisors (see below), whose sum is σ = 38400656. Its totient is φ = 10971612.

The previous prime is 21943213. The next prime is 21943231. The reversal of 21943228 is 82234912.

It is a self number, because there is not a number n which added to its sum of digits gives 21943228.

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, 2742900 + ... + 2742907.

Almost surely, 2^21943228 is an apocalyptic number.

It is an amenable number.

21943228 is a deficient number, since it is larger than the sum of its proper divisors (16457428).

21943228 is a wasteful number, since it uses less digits than its factorization.

21943228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5485811 (or 5485809 counting only the distinct ones).

The product of its digits is 6912, while the sum is 31.

The square root of 21943228 is about 4684.3599349324. The cubic root of 21943228 is about 279.9626991127.

The spelling of 21943228 in words is "twenty-one million, nine hundred forty-three thousand, two hundred twenty-eight".