217923713291 has 2 divisors, whose sum is σ = 217923713292. Its totient is φ = 217923713290.

The previous prime is 217923713263. The next prime is 217923713389. The reversal of 217923713291 is 192317329712.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 217923713291 - 2¹⁰ = 217923712267 is a prime.

It is not a weakly prime, because it can be changed into another prime (217923713191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108961856645 + 108961856646.

It is an arithmetic number, because the mean of its divisors is an integer number (108961856646).

Almost surely, 2^217923713291 is an apocalyptic number.

217923713291 is a deficient number, since it is larger than the sum of its proper divisors (1).

217923713291 is an equidigital number, since it uses as much as digits as its factorization.

217923713291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 285768, while the sum is 47.

The spelling of 217923713291 in words is "two hundred seventeen billion, nine hundred twenty-three million, seven hundred thirteen thousand, two hundred ninety-one".