217540233 has 24 divisors (see below), whose sum is σ = 329596800. Its totient is φ = 137998080.

The previous prime is 217540231. The next prime is 217540243. The reversal of 217540233 is 332045712.

It is not a de Polignac number, because 217540233 - 2¹ = 217540231 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 217540197 and 217540206.

It is not an unprimeable number, because it can be changed into a prime (217540231) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 38553 + ... + 43833.

It is an arithmetic number, because the mean of its divisors is an integer number (13733200).

Almost surely, 2^217540233 is an apocalyptic number.

217540233 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

217540233 is a deficient number, since it is larger than the sum of its proper divisors (112056567).

217540233 is a wasteful number, since it uses less digits than its factorization.

217540233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5509 (or 5506 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 27.

The square root of 217540233 is about 14749.2451671264. The cubic root of 217540233 is about 601.4227652318.

Adding to 217540233 its reverse (332045712), we get a palindrome (549585945).

The spelling of 217540233 in words is "two hundred seventeen million, five hundred forty thousand, two hundred thirty-three".