243723256081 has 2 divisors, whose sum is σ = 243723256082. Its totient is φ = 243723256080.

The previous prime is 243723255967. The next prime is 243723256087. The reversal of 243723256081 is 180652327342.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 214406967681 + 29316288400 = 463041^2 + 171220^2 .

It is a cyclic number.

It is not a de Polignac number, because 243723256081 - 2³⁷ = 106284302609 is a prime.

It is a super-2 number, since 2×243723256081² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (243723256087) 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, 121861628040 + 121861628041.

It is an arithmetic number, because the mean of its divisors is an integer number (121861628041).

Almost surely, 2^243723256081 is an apocalyptic number.

It is an amenable number.

243723256081 is a deficient number, since it is larger than the sum of its proper divisors (1).

243723256081 is an equidigital number, since it uses as much as digits as its factorization.

243723256081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 483840, while the sum is 43.

The spelling of 243723256081 in words is "two hundred forty-three billion, seven hundred twenty-three million, two hundred fifty-six thousand, eighty-one".