21241436221 has 2 divisors, whose sum is σ = 21241436222. Its totient is φ = 21241436220.

The previous prime is 21241436219. The next prime is 21241436239. The reversal of 21241436221 is 12263414212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17195076900 + 4046359321 = 131130^2 + 63611^2 .

It is a cyclic number.

It is not a de Polignac number, because 21241436221 - 2¹ = 21241436219 is a prime.

It is a super-2 number, since 2×21241436221² (a number of 21 digits) contains 22 as substring.

Together with 21241436219, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21241436221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21241436621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10620718110 + 10620718111.

It is an arithmetic number, because the mean of its divisors is an integer number (10620718111).

Almost surely, 2^21241436221 is an apocalyptic number.

It is an amenable number.

21241436221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21241436221 is an equidigital number, since it uses as much as digits as its factorization.

21241436221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4608, while the sum is 28.

The spelling of 21241436221 in words is "twenty-one billion, two hundred forty-one million, four hundred thirty-six thousand, two hundred twenty-one".