225521 has 4 divisors (see below), whose sum is σ = 227700. Its totient is φ = 223344.

The previous prime is 225509. The next prime is 225523. The reversal of 225521 is 125522.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 125522 = 2 ⋅62761.

It can be written as a sum of positive squares in 2 ways, for example, as 93025 + 132496 = 305^2 + 364^2 .

It is a cyclic number.

It is not a de Polignac number, because 225521 - 2⁶ = 225457 is a prime.

It is a Duffinian number.

It is a plaindrome in base 11.

It is a self number, because there is not a number n which added to its sum of digits gives 225521.

It is not an unprimeable number, because it can be changed into a prime (225523) 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, 926 + ... + 1143.

It is an arithmetic number, because the mean of its divisors is an integer number (56925).

2²²⁵⁵²¹ is an apocalyptic number.

It is an amenable number.

225521 is a deficient number, since it is larger than the sum of its proper divisors (2179).

225521 is a wasteful number, since it uses less digits than its factorization.

225521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2178.

The product of its digits is 200, while the sum is 17.

The square root of 225521 is about 474.8905136976. The cubic root of 225521 is about 60.8689293560.

Subtracting from 225521 its reverse (125522), we obtain a palindrome (99999).

The spelling of 225521 in words is "two hundred twenty-five thousand, five hundred twenty-one".