243997811 has 2 divisors, whose sum is σ = 243997812. Its totient is φ = 243997810.

The previous prime is 243997769. The next prime is 243997843. The reversal of 243997811 is 118799342.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243997811 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (243997891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121998905 + 121998906.

It is an arithmetic number, because the mean of its divisors is an integer number (121998906).

Almost surely, 2^243997811 is an apocalyptic number.

243997811 is a deficient number, since it is larger than the sum of its proper divisors (1).

243997811 is an equidigital number, since it uses as much as digits as its factorization.

243997811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108864, while the sum is 44.

The square root of 243997811 is about 15620.4292834736. The cubic root of 243997811 is about 624.8781082827.

The spelling of 243997811 in words is "two hundred forty-three million, nine hundred ninety-seven thousand, eight hundred eleven".