221540 has 48 divisors (see below), whose sum is σ = 544320. Its totient is φ = 74880.

The previous prime is 221539. The next prime is 221549. The reversal of 221540 is 45122.

It is not an unprimeable number, because it can be changed into a prime (221549) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4154 + ... + 4206.

It is an arithmetic number, because the mean of its divisors is an integer number (11340).

2²²¹⁵⁴⁰ is an apocalyptic number.

221540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (272160).

221540 is an abundant number, since it is smaller than the sum of its proper divisors (322780).

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

221540 is a wasteful number, since it uses less digits than its factorization.

221540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92 (or 90 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 14.

The square root of 221540 is about 470.6803586299. The cubic root of 221540 is about 60.5086388866.

Adding to 221540 its reverse (45122), we get a palindrome (266662).

The spelling of 221540 in words is "two hundred twenty-one thousand, five hundred forty".