217712240657 has 2 divisors, whose sum is σ = 217712240658. Its totient is φ = 217712240656.

The previous prime is 217712240611. The next prime is 217712240659. The reversal of 217712240657 is 756042217712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 193599120001 + 24113120656 = 439999^2 + 155284^2 .

It is a cyclic number.

It is not a de Polignac number, because 217712240657 - 2⁸ = 217712240401 is a prime.

Together with 217712240659, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (217712240659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108856120328 + 108856120329.

It is an arithmetic number, because the mean of its divisors is an integer number (108856120329).

Almost surely, 2^217712240657 is an apocalyptic number.

It is an amenable number.

217712240657 is a deficient number, since it is larger than the sum of its proper divisors (1).

217712240657 is an equidigital number, since it uses as much as digits as its factorization.

217712240657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 329280, while the sum is 44.

The spelling of 217712240657 in words is "two hundred seventeen billion, seven hundred twelve million, two hundred forty thousand, six hundred fifty-seven".