217047091 has 2 divisors, whose sum is σ = 217047092. Its totient is φ = 217047090.

The previous prime is 217047079. The next prime is 217047097. The reversal of 217047091 is 190740712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 217047091 - 2¹⁵ = 217014323 is a prime.

It is not a weakly prime, because it can be changed into another prime (217047097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108523545 + 108523546.

It is an arithmetic number, because the mean of its divisors is an integer number (108523546).

Almost surely, 2^217047091 is an apocalyptic number.

217047091 is a deficient number, since it is larger than the sum of its proper divisors (1).

217047091 is an equidigital number, since it uses as much as digits as its factorization.

217047091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3528, while the sum is 31.

The square root of 217047091 is about 14732.5181486398. The cubic root of 217047091 is about 600.9679662661.

The spelling of 217047091 in words is "two hundred seventeen million, forty-seven thousand, ninety-one".