221331132 has 72 divisors (see below), whose sum is σ = 631416240. Its totient is φ = 64753920.

The previous prime is 221331107. The next prime is 221331137. The reversal of 221331132 is 231133122.

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221331137) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1848 + ... + 21120.

It is an arithmetic number, because the mean of its divisors is an integer number (8769670).

Almost surely, 2^221331132 is an apocalyptic number.

221331132 is a gapful number since it is divisible by the number (22) 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 221331132, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (315708120).

221331132 is an abundant number, since it is smaller than the sum of its proper divisors (410085108).

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

221331132 is a wasteful number, since it uses less digits than its factorization.

221331132 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19323 (or 19318 counting only the distinct ones).

The product of its digits is 216, while the sum is 18.

The square root of 221331132 is about 14877.2017530179. The cubic root of 221331132 is about 604.8961705115.

Adding to 221331132 its reverse (231133122), we get a palindrome (452464254).

The spelling of 221331132 in words is "two hundred twenty-one million, three hundred thirty-one thousand, one hundred thirty-two".