205815472128 has 448 divisors, whose sum is σ = 700783480320. Its totient is φ = 58477510656.

The previous prime is 205815472123. The next prime is 205815472171. The reversal of 205815472128 is 821274518502.

205815472128 is a `hidden beast` number, since 2 + 0 + 5 + 81 + 547 + 2 + 1 + 28 = 666.

It is a tau number, because it is divible by the number of its divisors (448).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205815472123) 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, 475324200 + ... + 475324632.

It is an arithmetic number, because the mean of its divisors is an integer number (1564248840).

Almost surely, 2^205815472128 is an apocalyptic number.

205815472128 is a gapful number since it is divisible by the number (28) 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 205815472128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (350391740160).

205815472128 is an abundant number, since it is smaller than the sum of its proper divisors (494968008192).

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

205815472128 is an equidigital number, since it uses as much as digits as its factorization.

205815472128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 782 (or 752 counting only the distinct ones).

The product of its (nonzero) digits is 358400, while the sum is 45.

The spelling of 205815472128 in words is "two hundred five billion, eight hundred fifteen million, four hundred seventy-two thousand, one hundred twenty-eight".