21442113421 has 2 divisors, whose sum is σ = 21442113422. Its totient is φ = 21442113420.

The previous prime is 21442113391. The next prime is 21442113461. The reversal of 21442113421 is 12431124412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14985187396 + 6456926025 = 122414^2 + 80355^2 .

It is a cyclic number.

It is not a de Polignac number, because 21442113421 - 2⁵ = 21442113389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21442113461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10721056710 + 10721056711.

It is an arithmetic number, because the mean of its divisors is an integer number (10721056711).

Almost surely, 2^21442113421 is an apocalyptic number.

It is an amenable number.

21442113421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21442113421 is an equidigital number, since it uses as much as digits as its factorization.

21442113421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1536, while the sum is 25.

Adding to 21442113421 its reverse (12431124412), we get a palindrome (33873237833).

The spelling of 21442113421 in words is "twenty-one billion, four hundred forty-two million, one hundred thirteen thousand, four hundred twenty-one".