217632608681 has 2 divisors, whose sum is σ = 217632608682. Its totient is φ = 217632608680.

The previous prime is 217632608623. The next prime is 217632608731. The reversal of 217632608681 is 186806236712.

217632608681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an a-pointer prime, because the next prime (217632608731) can be obtained adding 217632608681 to its sum of digits (50).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 138268704025 + 79363904656 = 371845^2 + 281716^2 .

It is a cyclic number.

It is not a de Polignac number, because 217632608681 - 2¹⁰ = 217632607657 is a prime.

It is a super-2 number, since 2×217632608681² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (217632608621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108816304340 + 108816304341.

It is an arithmetic number, because the mean of its divisors is an integer number (108816304341).

Almost surely, 2^217632608681 is an apocalyptic number.

It is an amenable number.

217632608681 is a deficient number, since it is larger than the sum of its proper divisors (1).

217632608681 is an equidigital number, since it uses as much as digits as its factorization.

217632608681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1161216, while the sum is 50.

The spelling of 217632608681 in words is "two hundred seventeen billion, six hundred thirty-two million, six hundred eight thousand, six hundred eighty-one".