21442412021 has 2 divisors, whose sum is σ = 21442412022. Its totient is φ = 21442412020.

The previous prime is 21442411897. The next prime is 21442412029. The reversal of 21442412021 is 12021424412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18970930225 + 2471481796 = 137735^2 + 49714^2 .

It is a cyclic number.

It is not a de Polignac number, because 21442412021 - 2¹⁸ = 21442149877 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21442412029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10721206010 + 10721206011.

It is an arithmetic number, because the mean of its divisors is an integer number (10721206011).

Almost surely, 2^21442412021 is an apocalyptic number.

It is an amenable number.

21442412021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21442412021 is an equidigital number, since it uses as much as digits as its factorization.

21442412021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1024, while the sum is 23.

Adding to 21442412021 its reverse (12021424412), we get a palindrome (33463836433).

The spelling of 21442412021 in words is "twenty-one billion, four hundred forty-two million, four hundred twelve thousand, twenty-one".