205640520 has 32 divisors (see below), whose sum is σ = 616921920. Its totient is φ = 54837440.

The previous prime is 205640509. The next prime is 205640527. The reversal of 205640520 is 25046502.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (205640527) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 856716 + ... + 856955.

It is an arithmetic number, because the mean of its divisors is an integer number (19278810).

Almost surely, 2^205640520 is an apocalyptic number.

205640520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

205640520 is an abundant number, since it is smaller than the sum of its proper divisors (411281400).

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

205640520 is a wasteful number, since it uses less digits than its factorization.

205640520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1713685 (or 1713681 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 205640520 is about 14340.1715470911. The cubic root of 205640520 is about 590.2503199043.

The spelling of 205640520 in words is "two hundred five million, six hundred forty thousand, five hundred twenty".