217440871 has 2 divisors, whose sum is σ = 217440872. Its totient is φ = 217440870.

The previous prime is 217440841. The next prime is 217440953. The reversal of 217440871 is 178044712.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217440871 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217440841) 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, 108720435 + 108720436.

It is an arithmetic number, because the mean of its divisors is an integer number (108720436).

Almost surely, 2^217440871 is an apocalyptic number.

217440871 is a deficient number, since it is larger than the sum of its proper divisors (1).

217440871 is an equidigital number, since it uses as much as digits as its factorization.

217440871 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12544, while the sum is 34.

The square root of 217440871 is about 14745.8764066433. The cubic root of 217440871 is about 601.3311842116.

The spelling of 217440871 in words is "two hundred seventeen million, four hundred forty thousand, eight hundred seventy-one".