21221241 has 4 divisors (see below), whose sum is σ = 28294992. Its totient is φ = 14147492.

The previous prime is 21221237. The next prime is 21221251. The reversal of 21221241 is 14212212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21221241 - 2² = 21221237 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21221241.

It is not an unprimeable number, because it can be changed into a prime (21221251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3536871 + ... + 3536876.

It is an arithmetic number, because the mean of its divisors is an integer number (7073748).

Almost surely, 2^21221241 is an apocalyptic number.

It is an amenable number.

21221241 is a deficient number, since it is larger than the sum of its proper divisors (7073751).

21221241 is an equidigital number, since it uses as much as digits as its factorization.

21221241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7073750.

The product of its digits is 64, while the sum is 15.

The square root of 21221241 is about 4606.6518210084. The cubic root of 21221241 is about 276.8579034602.

Adding to 21221241 its reverse (14212212), we get a palindrome (35433453).

The spelling of 21221241 in words is "twenty-one million, two hundred twenty-one thousand, two hundred forty-one".