217101312 has 66 divisors (see below), whose sum is σ = 626901938. Its totient is φ = 72364032.

The previous prime is 217101223. The next prime is 217101317. The reversal of 217101312 is 213101712.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 113550336 + 103550976 = 10656^2 + 10176^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217101317) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2563 + ... + 20994.

Almost surely, 2^217101312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 217101312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (313450969).

217101312 is an abundant number, since it is smaller than the sum of its proper divisors (409800626).

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

217101312 is a wasteful number, since it uses less digits than its factorization.

217101312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23583 (or 23562 counting only the distinct ones).

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

The square root of 217101312 is about 14734.3582147306. The cubic root of 217101312 is about 601.0180051324.

The spelling of 217101312 in words is "two hundred seventeen million, one hundred one thousand, three hundred twelve".