217667712266861 has 2 divisors, whose sum is σ = 217667712266862. Its totient is φ = 217667712266860.

The previous prime is 217667712266843. The next prime is 217667712266887. The reversal of 217667712266861 is 168662217766712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 139828118111236 + 77839594155625 = 11824894^2 + 8822675^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217667712266861 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 217667712266791 and 217667712266800.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217667712236861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108833856133430 + 108833856133431.

It is an arithmetic number, because the mean of its divisors is an integer number (108833856133431).

Almost surely, 2^{217667712266861} is an apocalyptic number.

It is an amenable number.

217667712266861 is a deficient number, since it is larger than the sum of its proper divisors (1).

217667712266861 is an equidigital number, since it uses as much as digits as its factorization.

217667712266861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 170698752, while the sum is 68.

The spelling of 217667712266861 in words is "two hundred seventeen trillion, six hundred sixty-seven billion, seven hundred twelve million, two hundred sixty-six thousand, eight hundred sixty-one".