21220243001 has 2 divisors, whose sum is σ = 21220243002. Its totient is φ = 21220243000.

The previous prime is 21220242971. The next prime is 21220243019. The reversal of 21220243001 is 10034202212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15640003600 + 5580239401 = 125060^2 + 74701^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220243001 - 2¹⁸ = 21219980857 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21220243021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610121500 + 10610121501.

It is an arithmetic number, because the mean of its divisors is an integer number (10610121501).

Almost surely, 2^21220243001 is an apocalyptic number.

It is an amenable number.

21220243001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220243001 is an equidigital number, since it uses as much as digits as its factorization.

21220243001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 17.

Adding to 21220243001 its reverse (10034202212), we get a palindrome (31254445213).

The spelling of 21220243001 in words is "twenty-one billion, two hundred twenty million, two hundred forty-three thousand, one".