21443204441 has 2 divisors, whose sum is σ = 21443204442. Its totient is φ = 21443204440.

The previous prime is 21443204413. The next prime is 21443204443. The reversal of 21443204441 is 14440234412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14809916416 + 6633288025 = 121696^2 + 81445^2 .

It is a cyclic number.

It is not a de Polignac number, because 21443204441 - 2¹⁰ = 21443203417 is a prime.

It is a super-2 number, since 2×21443204441² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 21443204443, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21443204443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10721602220 + 10721602221.

It is an arithmetic number, because the mean of its divisors is an integer number (10721602221).

Almost surely, 2^21443204441 is an apocalyptic number.

It is an amenable number.

21443204441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21443204441 is an equidigital number, since it uses as much as digits as its factorization.

21443204441 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12288, while the sum is 29.

Adding to 21443204441 its reverse (14440234412), we get a palindrome (35883438853).

The spelling of 21443204441 in words is "twenty-one billion, four hundred forty-three million, two hundred four thousand, four hundred forty-one".