217097987 has 2 divisors, whose sum is σ = 217097988. Its totient is φ = 217097986.

The previous prime is 217097953. The next prime is 217097999. The reversal of 217097987 is 789790712.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217097987 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (217097087) 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, 108548993 + 108548994.

It is an arithmetic number, because the mean of its divisors is an integer number (108548994).

Almost surely, 2^217097987 is an apocalyptic number.

217097987 is a deficient number, since it is larger than the sum of its proper divisors (1).

217097987 is an equidigital number, since it uses as much as digits as its factorization.

217097987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 444528, while the sum is 50.

The square root of 217097987 is about 14734.2453827809. The cubic root of 217097987 is about 601.0149368336.

The spelling of 217097987 in words is "two hundred seventeen million, ninety-seven thousand, nine hundred eighty-seven".