217104681 has 4 divisors (see below), whose sum is σ = 289472912. Its totient is φ = 144736452.

The previous prime is 217104661. The next prime is 217104733. The reversal of 217104681 is 186401712.

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 217104681 - 2⁵ = 217104649 is a prime.

It is a super-2 number, since 2×217104681² = 94268885024223522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217104661) 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, 36184111 + ... + 36184116.

It is an arithmetic number, because the mean of its divisors is an integer number (72368228).

Almost surely, 2^217104681 is an apocalyptic number.

It is an amenable number.

217104681 is a deficient number, since it is larger than the sum of its proper divisors (72368231).

217104681 is an equidigital number, since it uses as much as digits as its factorization.

217104681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72368230.

The product of its (nonzero) digits is 2688, while the sum is 30.

The square root of 217104681 is about 14734.4725389136. The cubic root of 217104681 is about 601.0211140023.

The spelling of 217104681 in words is "two hundred seventeen million, one hundred four thousand, six hundred eighty-one".