217385472 has 80 divisors (see below), whose sum is σ = 582275232. Its totient is φ = 72069120.

The previous prime is 217385447. The next prime is 217385491. The reversal of 217385472 is 274583712.

It is a self number, because there is not a number n which added to its sum of digits gives 217385472.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 471322 + ... + 471782.

Almost surely, 2^217385472 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 217385472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (291137616).

217385472 is an abundant number, since it is smaller than the sum of its proper divisors (364889760).

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

217385472 is an equidigital number, since it uses as much as digits as its factorization.

217385472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 789 (or 773 counting only the distinct ones).

The product of its digits is 94080, while the sum is 39.

The square root of 217385472 is about 14743.9978296255. The cubic root of 217385472 is about 601.2801113603.

The spelling of 217385472 in words is "two hundred seventeen million, three hundred eighty-five thousand, four hundred seventy-two".