217778956247 has 2 divisors, whose sum is σ = 217778956248. Its totient is φ = 217778956246.

The previous prime is 217778956207. The next prime is 217778956303. The reversal of 217778956247 is 742659877712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 217778956247 - 2²⁰ = 217777907671 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217778956207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108889478123 + 108889478124.

It is an arithmetic number, because the mean of its divisors is an integer number (108889478124).

Almost surely, 2^217778956247 is an apocalyptic number.

217778956247 is a deficient number, since it is larger than the sum of its proper divisors (1).

217778956247 is an equidigital number, since it uses as much as digits as its factorization.

217778956247 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82978560, while the sum is 65.

The spelling of 217778956247 in words is "two hundred seventeen billion, seven hundred seventy-eight million, nine hundred fifty-six thousand, two hundred forty-seven".