217971968 has 36 divisors (see below), whose sum is σ = 437021508. Its totient is φ = 108503040.

The previous prime is 217971967. The next prime is 217971991. The reversal of 217971968 is 869179712.

217971968 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 171295744 + 46676224 = 13088^2 + 6832^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217971961) 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, 59930 + ... + 63462.

Almost surely, 2^217971968 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 217971968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (218510754).

217971968 is an abundant number, since it is smaller than the sum of its proper divisors (219049540).

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

217971968 is an equidigital number, since it uses as much as digits as its factorization.

217971968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3790 (or 3776 counting only the distinct ones).

The product of its digits is 381024, while the sum is 50.

The square root of 217971968 is about 14763.8737464122. The cubic root of 217971968 is about 601.8203678126.

It can be divided in two parts, 2179 and 71968, that added together give a palindrome (74147).

The spelling of 217971968 in words is "two hundred seventeen million, nine hundred seventy-one thousand, nine hundred sixty-eight".