221500 has 24 divisors (see below), whose sum is σ = 484848. Its totient is φ = 88400.

The previous prime is 221497. The next prime is 221509. The reversal of 221500 is 5122.

221500 is nontrivially palindromic in base 6.

221500 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221509) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 279 + ... + 721.

It is an arithmetic number, because the mean of its divisors is an integer number (20202).

2²²¹⁵⁰⁰ is an apocalyptic number.

221500 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 221500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (242424).

221500 is an abundant number, since it is smaller than the sum of its proper divisors (263348).

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

221500 is a wasteful number, since it uses less digits than its factorization.

221500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 462 (or 450 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 10.

The square root of 221500 is about 470.6378650300. The cubic root of 221500 is about 60.5049969690.

Adding to 221500 its reverse (5122), we get a palindrome (226622).

The spelling of 221500 in words is "two hundred twenty-one thousand, five hundred".