217917057691 has 2 divisors, whose sum is σ = 217917057692. Its totient is φ = 217917057690.

The previous prime is 217917057679. The next prime is 217917057707. The reversal of 217917057691 is 196750719712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 217917057691 - 2¹³ = 217917049499 is a prime.

It is not a weakly prime, because it can be changed into another prime (217917057661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108958528845 + 108958528846.

It is an arithmetic number, because the mean of its divisors is an integer number (108958528846).

Almost surely, 2^217917057691 is an apocalyptic number.

217917057691 is a deficient number, since it is larger than the sum of its proper divisors (1).

217917057691 is an equidigital number, since it uses as much as digits as its factorization.

217917057691 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1666980, while the sum is 55.

The spelling of 217917057691 in words is "two hundred seventeen billion, nine hundred seventeen million, fifty-seven thousand, six hundred ninety-one".