247691 has 2 divisors, whose sum is σ = 247692. Its totient is φ = 247690.

The previous prime is 247651. The next prime is 247693. The reversal of 247691 is 196742.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-247691 is a prime.

It is a super-2 number, since 2×247691² = 122701662962, which contains 22 as substring.

Together with 247693, it forms a pair of twin primes.

It is a Chen prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 247691.

It is not a weakly prime, because it can be changed into another prime (247693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 123845 + 123846.

It is an arithmetic number, because the mean of its divisors is an integer number (123846).

2²⁴⁷⁶⁹¹ is an apocalyptic number.

247691 is a deficient number, since it is larger than the sum of its proper divisors (1).

247691 is an equidigital number, since it uses as much as digits as its factorization.

247691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 29.

The square root of 247691 is about 497.6856437552. The cubic root of 247691 is about 62.8015084766.

The spelling of 247691 in words is "two hundred forty-seven thousand, six hundred ninety-one".