217888081 has 2 divisors, whose sum is σ = 217888082. Its totient is φ = 217888080.

The previous prime is 217888061. The next prime is 217888127. The reversal of 217888081 is 180888712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 187251856 + 30636225 = 13684^2 + 5535^2 .

It is a cyclic number.

It is not a de Polignac number, because 217888081 - 2¹³ = 217879889 is a prime.

It is a super-2 number, since 2×217888081² = 94950431683725122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (217888051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108944040 + 108944041.

It is an arithmetic number, because the mean of its divisors is an integer number (108944041).

Almost surely, 2^217888081 is an apocalyptic number.

It is an amenable number.

217888081 is a deficient number, since it is larger than the sum of its proper divisors (1).

217888081 is an equidigital number, since it uses as much as digits as its factorization.

217888081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 57344, while the sum is 43.

The square root of 217888081 is about 14761.0325180863. The cubic root of 217888081 is about 601.7431539344.

The spelling of 217888081 in words is "two hundred seventeen million, eight hundred eighty-eight thousand, eighty-one".