21726228 has 24 divisors (see below), whose sum is σ = 51932160. Its totient is φ = 7065280.

The previous prime is 21726227. The next prime is 21726233. The reversal of 21726228 is 82262712.

It is a junction number, because it is equal to n+sod(n) for n = 21726195 and 21726204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21726227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21588 + ... + 22571.

It is an arithmetic number, because the mean of its divisors is an integer number (2163840).

Almost surely, 2^21726228 is an apocalyptic number.

It is an amenable number.

21726228 is an abundant number, since it is smaller than the sum of its proper divisors (30205932).

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

21726228 is a wasteful number, since it uses less digits than its factorization.

21726228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44207 (or 44205 counting only the distinct ones).

The product of its digits is 5376, while the sum is 30.

The square root of 21726228 is about 4661.1402038557. The cubic root of 21726228 is about 279.0367752554.

The spelling of 21726228 in words is "twenty-one million, seven hundred twenty-six thousand, two hundred twenty-eight".