243311212021 has 2 divisors, whose sum is σ = 243311212022. Its totient is φ = 243311212020.

The previous prime is 243311212019. The next prime is 243311212033. The reversal of 243311212021 is 120212113342.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 198836619921 + 44474592100 = 445911^2 + 210890^2 .

It is a cyclic number.

It is not a de Polignac number, because 243311212021 - 2¹ = 243311212019 is a prime.

Together with 243311212019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 243311211983 and 243311212001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243311212061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121655606010 + 121655606011.

It is an arithmetic number, because the mean of its divisors is an integer number (121655606011).

Almost surely, 2^243311212021 is an apocalyptic number.

It is an amenable number.

243311212021 is a deficient number, since it is larger than the sum of its proper divisors (1).

243311212021 is an equidigital number, since it uses as much as digits as its factorization.

243311212021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 22.

Adding to 243311212021 its reverse (120212113342), we get a palindrome (363523325363).

The spelling of 243311212021 in words is "two hundred forty-three billion, three hundred eleven million, two hundred twelve thousand, twenty-one".