217031172 has 12 divisors (see below), whose sum is σ = 506406096. Its totient is φ = 72343720.

The previous prime is 217031137. The next prime is 217031179. The reversal of 217031172 is 271130712.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (217031179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9042954 + ... + 9042977.

It is an arithmetic number, because the mean of its divisors is an integer number (42200508).

Almost surely, 2^217031172 is an apocalyptic number.

It is an amenable number.

217031172 is an abundant number, since it is smaller than the sum of its proper divisors (289374924).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

217031172 is a wasteful number, since it uses less digits than its factorization.

217031172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18085938 (or 18085936 counting only the distinct ones).

The product of its (nonzero) digits is 588, while the sum is 24.

The square root of 217031172 is about 14731.9778712840. The cubic root of 217031172 is about 600.9532735361.

Adding to 217031172 its reverse (271130712), we get a palindrome (488161884).

The spelling of 217031172 in words is "two hundred seventeen million, thirty-one thousand, one hundred seventy-two".