216742217 has 2 divisors, whose sum is σ = 216742218. Its totient is φ = 216742216.

The previous prime is 216742213. The next prime is 216742219. The reversal of 216742217 is 712247612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 199261456 + 17480761 = 14116^2 + 4181^2 .

It is a cyclic number.

It is not a de Polignac number, because 216742217 - 2² = 216742213 is a prime.

Together with 216742219, 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 (216742213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108371108 + 108371109.

It is an arithmetic number, because the mean of its divisors is an integer number (108371109).

Almost surely, 2^216742217 is an apocalyptic number.

It is an amenable number.

216742217 is a deficient number, since it is larger than the sum of its proper divisors (1).

216742217 is an equidigital number, since it uses as much as digits as its factorization.

216742217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9408, while the sum is 32.

The square root of 216742217 is about 14722.1675374246. The cubic root of 216742217 is about 600.6864523022.

Adding to 216742217 its reverse (712247612), we get a palindrome (928989829).

The spelling of 216742217 in words is "two hundred sixteen million, seven hundred forty-two thousand, two hundred seventeen".