205104505240 has 128 divisors (see below), whose sum is σ = 492547968000. Its totient is φ = 76642495488.

The previous prime is 205104505237. The next prime is 205104505241. The reversal of 205104505240 is 42505401502.

It is a junction number, because it is equal to n+sod(n) for n = 205104505199 and 205104505208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205104505241) 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, 62019667 + ... + 62022973.

It is an arithmetic number, because the mean of its divisors is an integer number (3848031000).

Almost surely, 2^205104505240 is an apocalyptic number.

205104505240 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 205104505240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (246273984000).

205104505240 is an abundant number, since it is smaller than the sum of its proper divisors (287443462760).

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

205104505240 is a wasteful number, since it uses less digits than its factorization.

205104505240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4449 (or 4445 counting only the distinct ones).

The product of its (nonzero) digits is 8000, while the sum is 28.

Adding to 205104505240 its reverse (42505401502), we get a palindrome (247609906742).

The spelling of 205104505240 in words is "two hundred five billion, one hundred four million, five hundred five thousand, two hundred forty".