205856640 has 480 divisors, whose sum is σ = 846414360. Its totient is φ = 47278080.

The previous prime is 205856633. The next prime is 205856669. The reversal of 205856640 is 46658502.

205856640 is a `hidden beast` number, since 2 + 0 + 5 + 8 + 5 + 6 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 205856595 and 205856604.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 10834551 + ... + 10834569.

Almost surely, 2^205856640 is an apocalyptic number.

205856640 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 205856640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (423207180).

205856640 is an abundant number, since it is smaller than the sum of its proper divisors (640557720).

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

205856640 is a wasteful number, since it uses less digits than its factorization.

205856640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80 (or 40 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 205856640 is about 14347.7050429677. The cubic root of 205856640 is about 590.4570240380.

It can be divided in two parts, 20585 and 6640, that added together give a square (27225 = 165²).

The spelling of 205856640 in words is "two hundred five million, eight hundred fifty-six thousand, six hundred forty".