218117217 has 4 divisors (see below), whose sum is σ = 290822960. Its totient is φ = 145411476.

The previous prime is 218117203. The next prime is 218117219. The reversal of 218117217 is 712711812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 218117217 - 2⁴ = 218117201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218117219) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36352867 + ... + 36352872.

It is an arithmetic number, because the mean of its divisors is an integer number (72705740).

Almost surely, 2^218117217 is an apocalyptic number.

It is an amenable number.

218117217 is a deficient number, since it is larger than the sum of its proper divisors (72705743).

218117217 is an equidigital number, since it uses as much as digits as its factorization.

218117217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72705742.

The product of its digits is 1568, while the sum is 30.

The square root of 218117217 is about 14768.7919952852. The cubic root of 218117217 is about 601.9540155749.

The spelling of 218117217 in words is "two hundred eighteen million, one hundred seventeen thousand, two hundred seventeen".