21442202021 has 2 divisors, whose sum is σ = 21442202022. Its totient is φ = 21442202020.

The previous prime is 21442201943. The next prime is 21442202029. The reversal of 21442202021 is 12020224412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19861264900 + 1580937121 = 140930^2 + 39761^2 .

It is a cyclic number.

It is not a de Polignac number, because 21442202021 - 2¹⁴ = 21442185637 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21442201984 and 21442202002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21442202029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10721101010 + 10721101011.

It is an arithmetic number, because the mean of its divisors is an integer number (10721101011).

Almost surely, 2^21442202021 is an apocalyptic number.

It is an amenable number.

21442202021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21442202021 is an equidigital number, since it uses as much as digits as its factorization.

21442202021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 21442202021 its reverse (12020224412), we get a palindrome (33462426433).

The spelling of 21442202021 in words is "twenty-one billion, four hundred forty-two million, two hundred two thousand, twenty-one".