217011231 has 20 divisors (see below), whose sum is σ = 325078600. Its totient is φ = 144272016.

The previous prime is 217011229. The next prime is 217011251. The reversal of 217011231 is 132110712.

It is a happy number.

It is not a de Polignac number, because 217011231 - 2¹ = 217011229 is a prime.

It is a super-2 number, since 2×217011231² = 94187748760270722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217011211) 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 in 19 ways as a sum of consecutive naturals, for example, 27165 + ... + 34233.

It is an arithmetic number, because the mean of its divisors is an integer number (16253930).

Almost surely, 2^217011231 is an apocalyptic number.

217011231 is a deficient number, since it is larger than the sum of its proper divisors (108067369).

217011231 is an equidigital number, since it uses as much as digits as its factorization.

217011231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7460 (or 7451 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 18.

The square root of 217011231 is about 14731.3010627032. The cubic root of 217011231 is about 600.9348676144.

Adding to 217011231 its reverse (132110712), we get a palindrome (349121943).

The spelling of 217011231 in words is "two hundred seventeen million, eleven thousand, two hundred thirty-one".