243123191 has 2 divisors, whose sum is σ = 243123192. Its totient is φ = 243123190.

The previous prime is 243123149. The next prime is 243123193. The reversal of 243123191 is 191321342.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 243123191 - 2²⁶ = 176014327 is a prime.

Together with 243123193, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 243123191.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243123193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121561595 + 121561596.

It is an arithmetic number, because the mean of its divisors is an integer number (121561596).

Almost surely, 2^243123191 is an apocalyptic number.

243123191 is a deficient number, since it is larger than the sum of its proper divisors (1).

243123191 is an equidigital number, since it uses as much as digits as its factorization.

243123191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1296, while the sum is 26.

The square root of 243123191 is about 15592.4081206208. The cubic root of 243123191 is about 624.1305807905.

The spelling of 243123191 in words is "two hundred forty-three million, one hundred twenty-three thousand, one hundred ninety-one".