221131 has 4 divisors (see below), whose sum is σ = 222264. Its totient is φ = 220000.

The previous prime is 221101. The next prime is 221159. The reversal of 221131 is 131122.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 221131 - 2¹¹ = 219083 is a prime.

It is a super-2 number, since 2×221131² = 97797838322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 190 + ... + 691.

It is an arithmetic number, because the mean of its divisors is an integer number (55566).

2²²¹¹³¹ is an apocalyptic number.

221131 is a deficient number, since it is larger than the sum of its proper divisors (1133).

221131 is an equidigital number, since it uses as much as digits as its factorization.

221131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1132.

The product of its digits is 12, while the sum is 10.

The square root of 221131 is about 470.2456804693. The cubic root of 221131 is about 60.4713795826.

Adding to 221131 its reverse (131122), we get a palindrome (352253).

Subtracting from 221131 its reverse (131122), we obtain a palindrome (90009).

The spelling of 221131 in words is "two hundred twenty-one thousand, one hundred thirty-one".