21242241 has 12 divisors (see below), whose sum is σ = 31262868. Its totient is φ = 13893984.

The previous prime is 21242237. The next prime is 21242339. The reversal of 21242241 is 14224212.

It can be written as a sum of positive squares in 2 ways, for example, as 13838400 + 7403841 = 3720^2 + 2721^2 .

It is not a de Polignac number, because 21242241 - 2² = 21242237 is a prime.

It is a super-4 number, since 4×21242241⁴ (a number of 30 digits) contains 4444 as substring.

It is not an unprimeable number, because it can be changed into a prime (21242201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21790 + ... + 22743.

It is an arithmetic number, because the mean of its divisors is an integer number (2605239).

Almost surely, 2^21242241 is an apocalyptic number.

It is an amenable number.

21242241 is a deficient number, since it is larger than the sum of its proper divisors (10020627).

21242241 is a wasteful number, since it uses less digits than its factorization.

21242241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44592 (or 44589 counting only the distinct ones).

The product of its digits is 256, while the sum is 18.

The square root of 21242241 is about 4608.9305700997. The cubic root of 21242241 is about 276.9491971979.

Adding to 21242241 its reverse (14224212), we get a palindrome (35466453).

The spelling of 21242241 in words is "twenty-one million, two hundred forty-two thousand, two hundred forty-one".