217813128 has 128 divisors (see below), whose sum is σ = 619315200. Its totient is φ = 63334656.

The previous prime is 217813111. The next prime is 217813147. The reversal of 217813128 is 821318712.

217813128 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 911233 + ... + 911471.

It is an arithmetic number, because the mean of its divisors is an integer number (4838400).

Almost surely, 2^217813128 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 217813128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (309657600).

217813128 is an abundant number, since it is smaller than the sum of its proper divisors (401502072).

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

217813128 is a wasteful number, since it uses less digits than its factorization.

217813128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 411 (or 407 counting only the distinct ones).

The product of its digits is 5376, while the sum is 33.

The square root of 217813128 is about 14758.4934190452. The cubic root of 217813128 is about 601.6741465995.

The spelling of 217813128 in words is "two hundred seventeen million, eight hundred thirteen thousand, one hundred twenty-eight".