21228241 has 6 divisors (see below), whose sum is σ = 22191890. Its totient is φ = 20304768.

The previous prime is 21228227. The next prime is 21228247. The reversal of 21228241 is 14282212.

It can be written as a sum of positive squares in only one way, i.e., 11587216 + 9641025 = 3404^2 + 3105^2 .

It is not a de Polignac number, because 21228241 - 2⁵ = 21228209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21228247) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 19536 + ... + 20593.

Almost surely, 2^21228241 is an apocalyptic number.

It is an amenable number.

21228241 is a deficient number, since it is larger than the sum of its proper divisors (963649).

21228241 is an equidigital number, since it uses as much as digits as its factorization.

21228241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40175 (or 40152 counting only the distinct ones).

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

The square root of 21228241 is about 4607.4115292646. The cubic root of 21228241 is about 276.8883413954. Note that the first 3 decimals are identical.

The spelling of 21228241 in words is "twenty-one million, two hundred twenty-eight thousand, two hundred forty-one".