21412221421 has 2 divisors, whose sum is σ = 21412221422. Its totient is φ = 21412221420.

The previous prime is 21412221409. The next prime is 21412221449. The reversal of 21412221421 is 12412221412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19659124521 + 1753096900 = 140211^2 + 41870^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21412221421 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21412221392 and 21412221401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21412221401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10706110710 + 10706110711.

It is an arithmetic number, because the mean of its divisors is an integer number (10706110711).

Almost surely, 2^21412221421 is an apocalyptic number.

It is an amenable number.

21412221421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21412221421 is an equidigital number, since it uses as much as digits as its factorization.

21412221421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 512, while the sum is 22.

Adding to 21412221421 its reverse (12412221412), we get a palindrome (33824442833).

Subtracting from 21412221421 its reverse (12412221412), we obtain a palindrome (9000000009).

The spelling of 21412221421 in words is "twenty-one billion, four hundred twelve million, two hundred twenty-one thousand, four hundred twenty-one".