217828997 has 2 divisors, whose sum is σ = 217828998. Its totient is φ = 217828996.

The previous prime is 217828981. The next prime is 217829009. The reversal of 217828997 is 799828712.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 162460516 + 55368481 = 12746^2 + 7441^2 .

It is a cyclic number.

It is not a de Polignac number, because 217828997 - 2⁴ = 217828981 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217828957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108914498 + 108914499.

It is an arithmetic number, because the mean of its divisors is an integer number (108914499).

Almost surely, 2^217828997 is an apocalyptic number.

It is an amenable number.

217828997 is a deficient number, since it is larger than the sum of its proper divisors (1).

217828997 is an equidigital number, since it uses as much as digits as its factorization.

217828997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1016064, while the sum is 53.

The square root of 217828997 is about 14759.0310318801. The cubic root of 217828997 is about 601.6887581081.

The spelling of 217828997 in words is "two hundred seventeen million, eight hundred twenty-eight thousand, nine hundred ninety-seven".