21432344323421 has 2 divisors, whose sum is σ = 21432344323422. Its totient is φ = 21432344323420.

The previous prime is 21432344323399. The next prime is 21432344323477. The reversal of 21432344323421 is 12432344323412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21323799772900 + 108544550521 = 4617770^2 + 329461^2 .

It is a cyclic number.

It is not a de Polignac number, because 21432344323421 - 2¹⁰ = 21432344322397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21432344320421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10716172161710 + 10716172161711.

It is an arithmetic number, because the mean of its divisors is an integer number (10716172161711).

Almost surely, 2^{21432344323421} is an apocalyptic number.

It is an amenable number.

21432344323421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21432344323421 is an equidigital number, since it uses as much as digits as its factorization.

21432344323421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 331776, while the sum is 38.

Adding to 21432344323421 its reverse (12432344323412), we get a palindrome (33864688646833).

Subtracting from 21432344323421 its reverse (12432344323412), we obtain a palindrome (9000000000009).

The spelling of 21432344323421 in words is "twenty-one trillion, four hundred thirty-two billion, three hundred forty-four million, three hundred twenty-three thousand, four hundred twenty-one".