217512172 has 12 divisors (see below), whose sum is σ = 381316936. Its totient is φ = 108564480.

The previous prime is 217512167. The next prime is 217512179. The reversal of 217512172 is 271215712.

It is a self number, because there is not a number n which added to its sum of digits gives 217512172.

It is not an unprimeable number, because it can be changed into a prime (217512179) 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, 45333 + ... + 49900.

Almost surely, 2^217512172 is an apocalyptic number.

It is an amenable number.

217512172 is a deficient number, since it is larger than the sum of its proper divisors (163804764).

217512172 is a wasteful number, since it uses less digits than its factorization.

217512172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95808 (or 95806 counting only the distinct ones).

The product of its digits is 1960, while the sum is 28.

The square root of 217512172 is about 14748.2938674275. The cubic root of 217512172 is about 601.3969044984.

Adding to 217512172 its reverse (271215712), we get a palindrome (488727884).

The spelling of 217512172 in words is "two hundred seventeen million, five hundred twelve thousand, one hundred seventy-two".