243221312137 has 2 divisors, whose sum is σ = 243221312138. Its totient is φ = 243221312136.

The previous prime is 243221312083. The next prime is 243221312141. The reversal of 243221312137 is 731213122342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 147975624976 + 95245687161 = 384676^2 + 308619^2 .

It is a cyclic number.

It is not a de Polignac number, because 243221312137 - 2²⁷ = 243087094409 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 243221312099 and 243221312108.

It is not a weakly prime, because it can be changed into another prime (243221312177) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121610656068 + 121610656069.

It is an arithmetic number, because the mean of its divisors is an integer number (121610656069).

Almost surely, 2^243221312137 is an apocalyptic number.

It is an amenable number.

243221312137 is a deficient number, since it is larger than the sum of its proper divisors (1).

243221312137 is an equidigital number, since it uses as much as digits as its factorization.

243221312137 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 31.

Adding to 243221312137 its reverse (731213122342), we get a palindrome (974434434479).

The spelling of 243221312137 in words is "two hundred forty-three billion, two hundred twenty-one million, three hundred twelve thousand, one hundred thirty-seven".