21043343440121 has 2 divisors, whose sum is σ = 21043343440122. Its totient is φ = 21043343440120.

The previous prime is 21043343440061. The next prime is 21043343440181. The reversal of 21043343440121 is 12104434334012.

It is a balanced prime because it is at equal distance from previous prime (21043343440061) and next prime (21043343440181).

It can be written as a sum of positive squares in only one way, i.e., 21042504758521 + 838681600 = 4587211^2 + 28960^2 .

It is a cyclic number.

It is not a de Polignac number, because 21043343440121 - 2⁶ = 21043343440057 is a prime.

It is not a weakly prime, because it can be changed into another prime (21043343440181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10521671720060 + 10521671720061.

It is an arithmetic number, because the mean of its divisors is an integer number (10521671720061).

Almost surely, 2^{21043343440121} is an apocalyptic number.

It is an amenable number.

21043343440121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21043343440121 is an equidigital number, since it uses as much as digits as its factorization.

21043343440121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27648, while the sum is 32.

Adding to 21043343440121 its reverse (12104434334012), we get a palindrome (33147777774133).

It can be divided in two parts, 2104334 and 3440121, that added together give a palindrome (5544455).

The spelling of 21043343440121 in words is "twenty-one trillion, forty-three billion, three hundred forty-three million, four hundred forty thousand, one hundred twenty-one".