217530 has 24 divisors (see below), whose sum is σ = 565812. Its totient is φ = 57984.

The previous prime is 217519. The next prime is 217559. The reversal of 217530 is 35712.

It can be written as a sum of positive squares in 2 ways, for example, as 205209 + 12321 = 453^2 + 111^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1119 + ... + 1298.

217530 is a Friedman number, since it can be written as 72510*3, using all its digits and the basic arithmetic operations.

2²¹⁷⁵³⁰ is an apocalyptic number.

217530 is an abundant number, since it is smaller than the sum of its proper divisors (348282).

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

217530 is a wasteful number, since it uses less digits than its factorization.

217530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2430 (or 2427 counting only the distinct ones).

The product of its (nonzero) digits is 210, while the sum is 18.

The square root of 217530 is about 466.4011149215. The cubic root of 217530 is about 60.1413334860.

It can be divided in two parts, 217 and 530, that added together give a palindrome (747).

The spelling of 217530 in words is "two hundred seventeen thousand, five hundred thirty".