21442104421 has 2 divisors, whose sum is σ = 21442104422. Its totient is φ = 21442104420.

The previous prime is 21442104379. The next prime is 21442104427. The reversal of 21442104421 is 12440124412.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18113391396 + 3328713025 = 134586^2 + 57695^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21442104421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21442104427) 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, 10721052210 + 10721052211.

It is an arithmetic number, because the mean of its divisors is an integer number (10721052211).

Almost surely, 2^21442104421 is an apocalyptic number.

It is an amenable number.

21442104421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21442104421 is an equidigital number, since it uses as much as digits as its factorization.

21442104421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2048, while the sum is 25.

Adding to 21442104421 its reverse (12440124412), we get a palindrome (33882228833).

The spelling of 21442104421 in words is "twenty-one billion, four hundred forty-two million, one hundred four thousand, four hundred twenty-one".