205640064 has 144 divisors (see below), whose sum is σ = 688552020. Its totient is φ = 58738176.

The previous prime is 205640063. The next prime is 205640077. The reversal of 205640064 is 460046502.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205640063) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 54627 + ... + 58269.

Almost surely, 2^205640064 is an apocalyptic number.

205640064 is a gapful number since it is divisible by the number (24) 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 205640064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (344276010).

205640064 is an abundant number, since it is smaller than the sum of its proper divisors (482911956).

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

205640064 is a wasteful number, since it uses less digits than its factorization.

205640064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3677 (or 3655 counting only the distinct ones).

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

The square root of 205640064 is about 14340.1556476909. The cubic root of 205640064 is about 590.2498836181.

Adding to 205640064 its reverse (460046502), we get a palindrome (665686566).

The spelling of 205640064 in words is "two hundred five million, six hundred forty thousand, sixty-four".