691075243 has 2 divisors, whose sum is σ = 691075244. Its totient is φ = 691075242.

The previous prime is 691075241. The next prime is 691075247. The reversal of 691075243 is 342570196.

691075243 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 691075243 - 2¹ = 691075241 is a prime.

Together with 691075241, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (691075241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345537621 + 345537622.

It is an arithmetic number, because the mean of its divisors is an integer number (345537622).

Almost surely, 2^691075243 is an apocalyptic number.

691075243 is a deficient number, since it is larger than the sum of its proper divisors (1).

691075243 is an equidigital number, since it uses as much as digits as its factorization.

691075243 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 45360, while the sum is 37.

The square root of 691075243 is about 26288.3100065409. The cubic root of 691075243 is about 884.1143610195.

The spelling of 691075243 in words is "six hundred ninety-one million, seventy-five thousand, two hundred forty-three".