43211221421 has 2 divisors, whose sum is σ = 43211221422. Its totient is φ = 43211221420.

The previous prime is 43211221387. The next prime is 43211221423. The reversal of 43211221421 is 12412211234.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42714555625 + 496665796 = 206675^2 + 22286^2 .

It is a cyclic number.

It is not a de Polignac number, because 43211221421 - 2³⁰ = 42137479597 is a prime.

Together with 43211221423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43211221423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21605610710 + 21605610711.

It is an arithmetic number, because the mean of its divisors is an integer number (21605610711).

Almost surely, 2^43211221421 is an apocalyptic number.

It is an amenable number.

43211221421 is a deficient number, since it is larger than the sum of its proper divisors (1).

43211221421 is an equidigital number, since it uses as much as digits as its factorization.

43211221421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 768, while the sum is 23.

Adding to 43211221421 its reverse (12412211234), we get a palindrome (55623432655).

The spelling of 43211221421 in words is "forty-three billion, two hundred eleven million, two hundred twenty-one thousand, four hundred twenty-one".