217056 has 96 divisors (see below), whose sum is σ = 725760. Its totient is φ = 55296.

The previous prime is 217033. The next prime is 217057. The reversal of 217056 is 650712.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×217056² = 94226614272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217057) by changing a digit.

217056 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11415 + ... + 11433.

It is an arithmetic number, because the mean of its divisors is an integer number (7560).

2²¹⁷⁰⁵⁶ 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 217056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (362880).

217056 is an abundant number, since it is smaller than the sum of its proper divisors (508704).

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

217056 is a wasteful number, since it uses less digits than its factorization.

217056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56 (or 48 counting only the distinct ones).

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 217056 is about 465.8926915074. The cubic root of 217056 is about 60.0976188676.

Adding to 217056 its reverse (650712), we get a palindrome (867768).

The spelling of 217056 in words is "two hundred seventeen thousand, fifty-six".