205604640 has 144 divisors (see below), whose sum is σ = 711861696. Its totient is φ = 54028800.

The previous prime is 205604621. The next prime is 205604669. The reversal of 205604640 is 46406502.

It is a happy number.

205604640 is a `hidden beast` number, since 20 + 560 + 46 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 101235 + ... + 103245.

It is an arithmetic number, because the mean of its divisors is an integer number (4943484).

Almost surely, 2^205604640 is an apocalyptic number.

205604640 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 205604640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (355930848).

205604640 is an abundant number, since it is smaller than the sum of its proper divisors (506257056).

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

205604640 is a wasteful number, since it uses less digits than its factorization.

205604640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2103 (or 2092 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 205604640 is about 14338.9204614573. The cubic root of 205604640 is about 590.2159891000.

It can be divided in two parts, 20560 and 4640, that added together give a triangular number (25200 = T₂₂₄).

The spelling of 205604640 in words is "two hundred five million, six hundred four thousand, six hundred forty".