205979680 has 24 divisors (see below), whose sum is σ = 486627372. Its totient is φ = 82391808.

The previous prime is 205979671. The next prime is 205979681. The reversal of 205979680 is 86979502.

It can be written as a sum of positive squares in 2 ways, for example, as 199487376 + 6492304 = 14124^2 + 2548^2 .

It is a Smith number, since the sum of its digits (46) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 205979680.

It is not an unprimeable number, because it can be changed into a prime (205979681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 643527 + ... + 643846.

Almost surely, 2^205979680 is an apocalyptic number.

205979680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

205979680 is an abundant number, since it is smaller than the sum of its proper divisors (280647692).

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

205979680 is a wasteful number, since it uses less digits than its factorization.

205979680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1287388 (or 1287380 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 46.

The square root of 205979680 is about 14351.9921962075. The cubic root of 205979680 is about 590.5746388384.

The spelling of 205979680 in words is "two hundred five million, nine hundred seventy-nine thousand, six hundred eighty".