217612289 has 2 divisors, whose sum is σ = 217612290. Its totient is φ = 217612288.

The previous prime is 217612267. The next prime is 217612327. The reversal of 217612289 is 982216712.

It is an a-pointer prime, because the next prime (217612327) can be obtained adding 217612289 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 215943025 + 1669264 = 14695^2 + 1292^2 .

It is a cyclic number.

It is not a de Polignac number, because 217612289 - 2²⁰ = 216563713 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (217612229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108806144 + 108806145.

It is an arithmetic number, because the mean of its divisors is an integer number (108806145).

It is a Proth number, since it is equal to 6641 ⋅ 2¹⁵ + 1 and 6641 < 2¹⁵.

Almost surely, 2^217612289 is an apocalyptic number.

It is an amenable number.

217612289 is a deficient number, since it is larger than the sum of its proper divisors (1).

217612289 is an equidigital number, since it uses as much as digits as its factorization.

217612289 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24192, while the sum is 38.

The square root of 217612289 is about 14751.6876661621. The cubic root of 217612289 is about 601.4891611260.

The spelling of 217612289 in words is "two hundred seventeen million, six hundred twelve thousand, two hundred eighty-nine".