217238143 has 2 divisors, whose sum is σ = 217238144. Its totient is φ = 217238142.

The previous prime is 217238129. The next prime is 217238171. The reversal of 217238143 is 341832712.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217238143 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217238543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108619071 + 108619072.

It is an arithmetic number, because the mean of its divisors is an integer number (108619072).

Almost surely, 2^217238143 is an apocalyptic number.

217238143 is a deficient number, since it is larger than the sum of its proper divisors (1).

217238143 is an equidigital number, since it uses as much as digits as its factorization.

217238143 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 31.

The square root of 217238143 is about 14739.0007463193. Note that the first 3 decimals coincide. The cubic root of 217238143 is about 601.1442451549.

The spelling of 217238143 in words is "two hundred seventeen million, two hundred thirty-eight thousand, one hundred forty-three".