221129 has 4 divisors (see below), whose sum is σ = 222084. Its totient is φ = 220176.

The previous prime is 221101. The next prime is 221159. The reversal of 221129 is 921122.

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, and also an emirpimes, since its reverse is a distinct semiprime: 921122 = 2 ⋅460561.

It can be written as a sum of positive squares in 2 ways, for example, as 76729 + 144400 = 277^2 + 380^2 .

It is a cyclic number.

It is not a de Polignac number, because 221129 - 2⁸ = 220873 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (221159) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 119 + ... + 675.

It is an arithmetic number, because the mean of its divisors is an integer number (55521).

2²²¹¹²⁹ is an apocalyptic number.

It is an amenable number.

221129 is a deficient number, since it is larger than the sum of its proper divisors (955).

221129 is an equidigital number, since it uses as much as digits as its factorization.

221129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 954.

The product of its digits is 72, while the sum is 17.

The square root of 221129 is about 470.2435539165. The cubic root of 221129 is about 60.4711972727.

The spelling of 221129 in words is "two hundred twenty-one thousand, one hundred twenty-nine".