205491920 has 80 divisors (see below), whose sum is σ = 514373328. Its totient is φ = 76062720.

The previous prime is 205491907. The next prime is 205491929. The reversal of 205491920 is 29194502.

It can be written as a sum of positive squares in 8 ways, for example, as 10163344 + 195328576 = 3188^2 + 13976^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205491929) 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, 81722 + ... + 84198.

Almost surely, 2^205491920 is an apocalyptic number.

205491920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 205491920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (257186664).

205491920 is an abundant number, since it is smaller than the sum of its proper divisors (308881408).

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

205491920 is a wasteful number, since it uses less digits than its factorization.

205491920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2568 (or 2562 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 205491920 is about 14334.9893616982. The cubic root of 205491920 is about 590.1081100367.

The spelling of 205491920 in words is "two hundred five million, four hundred ninety-one thousand, nine hundred twenty".