21414221 has 2 divisors, whose sum is σ = 21414222. Its totient is φ = 21414220.

The previous prime is 21414193. The next prime is 21414223. The reversal of 21414221 is 12241412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15721225 + 5692996 = 3965^2 + 2386^2 .

It is a cyclic number.

It is not a de Polignac number, because 21414221 - 2¹⁴ = 21397837 is a prime.

It is a super-2 number, since 2×21414221² = 917137722073682, which contains 22 as substring.

Together with 21414223, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21414221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21414223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10707110 + 10707111.

It is an arithmetic number, because the mean of its divisors is an integer number (10707111).

Almost surely, 2^21414221 is an apocalyptic number.

It is an amenable number.

21414221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21414221 is an equidigital number, since it uses as much as digits as its factorization.

21414221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 128, while the sum is 17.

The square root of 21414221 is about 4627.5502158269. The cubic root of 21414221 is about 277.6945949979.

Adding to 21414221 its reverse (12241412), we get a palindrome (33655633).

The spelling of 21414221 in words is "twenty-one million, four hundred fourteen thousand, two hundred twenty-one".