205120 has 28 divisors (see below), whose sum is σ = 489204. Its totient is φ = 81920.

The previous prime is 205111. The next prime is 205129. The reversal of 205120 is 21502.

205120 is a nontrivial binomial coefficient, being equal to C(641, 2).

It is an interprime number because it is at equal distance from previous prime (205111) and next prime (205129).

It can be written as a sum of positive squares in 2 ways, for example, as 135424 + 69696 = 368^2 + 264^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 205097 and 205106.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1 + ... + 640.

2²⁰⁵¹²⁰ is an apocalyptic number.

205120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

205120 is the 640-th triangular number.

205120 is the 214-th centered nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 205120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (244602).

205120 is an abundant number, since it is smaller than the sum of its proper divisors (284084).

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

205120 is an equidigital number, since it uses as much as digits as its factorization.

205120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 658 (or 648 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 10.

The square root of 205120 is about 452.9017553510. The cubic root of 205120 is about 58.9751882649.

Adding to 205120 its reverse (21502), we get a palindrome (226622).

It can be divided in two parts, 205 and 120, that added together give a triangular number (325 = T₂₅).

The spelling of 205120 in words is "two hundred five thousand, one hundred twenty".