225561 has 16 divisors (see below), whose sum is σ = 359424. Its totient is φ = 123024.

The previous prime is 225529. The next prime is 225569. The reversal of 225561 is 165522.

225561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 225561 - 2⁵ = 225529 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (225569) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 250 + ... + 716.

It is an arithmetic number, because the mean of its divisors is an integer number (22464).

2²²⁵⁵⁶¹ is an apocalyptic number.

225561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

225561 is a deficient number, since it is larger than the sum of its proper divisors (133863).

225561 is a wasteful number, since it uses less digits than its factorization.

225561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500.

The product of its digits is 600, while the sum is 21.

The square root of 225561 is about 474.9326268009. The cubic root of 225561 is about 60.8725278579.

The spelling of 225561 in words is "two hundred twenty-five thousand, five hundred sixty-one".