205389780 has 48 divisors (see below), whose sum is σ = 578647104. Its totient is φ = 54432000.

The previous prime is 205389763. The next prime is 205389781. The reversal of 205389780 is 87983502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205389781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 721 + ... + 20280.

It is an arithmetic number, because the mean of its divisors is an integer number (12055148).

Almost surely, 2^205389780 is an apocalyptic number.

205389780 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 205389780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (289323552).

205389780 is an abundant number, since it is smaller than the sum of its proper divisors (373257324).

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

205389780 is a wasteful number, since it uses less digits than its factorization.

205389780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21176 (or 21174 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 42.

The square root of 205389780 is about 14331.4263072452. The cubic root of 205389780 is about 590.0103225236.

The spelling of 205389780 in words is "two hundred five million, three hundred eighty-nine thousand, seven hundred eighty".