21324121243 has 2 divisors, whose sum is σ = 21324121244. Its totient is φ = 21324121242.

The previous prime is 21324121219. The next prime is 21324121297. The reversal of 21324121243 is 34212142312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21324121243 - 2²¹ = 21322024091 is a prime.

It is not a weakly prime, because it can be changed into another prime (21324121943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10662060621 + 10662060622.

It is an arithmetic number, because the mean of its divisors is an integer number (10662060622).

Almost surely, 2^21324121243 is an apocalyptic number.

21324121243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21324121243 is an equidigital number, since it uses as much as digits as its factorization.

21324121243 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 25.

Adding to 21324121243 its reverse (34212142312), we get a palindrome (55536263555).

The spelling of 21324121243 in words is "twenty-one billion, three hundred twenty-four million, one hundred twenty-one thousand, two hundred forty-three".