217081 has 2 divisors, whose sum is σ = 217082. Its totient is φ = 217080.

The previous prime is 217069. The next prime is 217111. The reversal of 217081 is 180712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 210681 + 6400 = 459^2 + 80^2 .

It is a cyclic number.

It is not a de Polignac number, because 217081 - 2⁹ = 216569 is a prime.

It is a super-2 number, since 2×217081² = 94248321122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (217001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108540 + 108541.

It is an arithmetic number, because the mean of its divisors is an integer number (108541).

2²¹⁷⁰⁸¹ is an apocalyptic number.

It is an amenable number.

217081 is a deficient number, since it is larger than the sum of its proper divisors (1).

217081 is an equidigital number, since it uses as much as digits as its factorization.

217081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112, while the sum is 19.

The square root of 217081 is about 465.9195209476. The cubic root of 217081 is about 60.0999260798.

Adding to 217081 its reverse (180712), we get a palindrome (397793).

The spelling of 217081 in words is "two hundred seventeen thousand, eighty-one".