247811 has 2 divisors, whose sum is σ = 247812. Its totient is φ = 247810.

The previous prime is 247799. The next prime is 247813. The reversal of 247811 is 118742.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 247811 - 2¹⁰ = 246787 is a prime.

It is a super-2 number, since 2×247811² = 122820583442, which contains 22 as substring.

Together with 247813, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (247813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 123905 + 123906.

It is an arithmetic number, because the mean of its divisors is an integer number (123906).

2²⁴⁷⁸¹¹ is an apocalyptic number.

247811 is a deficient number, since it is larger than the sum of its proper divisors (1).

247811 is an equidigital number, since it uses as much as digits as its factorization.

247811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 448, while the sum is 23.

The square root of 247811 is about 497.8061871853. The cubic root of 247811 is about 62.8116487513.

The spelling of 247811 in words is "two hundred forty-seven thousand, eight hundred eleven".