205311240 has 128 divisors (see below), whose sum is σ = 700444800. Its totient is φ = 53464320.

The previous prime is 205311221. The next prime is 205311247. The reversal of 205311240 is 42113502.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (205311247) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 44230 + ... + 48650.

It is an arithmetic number, because the mean of its divisors is an integer number (5472225).

Almost surely, 2^205311240 is an apocalyptic number.

205311240 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 205311240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (350222400).

205311240 is an abundant number, since it is smaller than the sum of its proper divisors (495133560).

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

205311240 is a wasteful number, since it uses less digits than its factorization.

205311240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4484 (or 4474 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 205311240 is about 14328.6859132301. The cubic root of 205311240 is about 589.9351072936.

Adding to 205311240 its reverse (42113502), we get a palindrome (247424742).

The spelling of 205311240 in words is "two hundred five million, three hundred eleven thousand, two hundred forty".