205720720 has 20 divisors (see below), whose sum is σ = 478300860. Its totient is φ = 82288256.

The previous prime is 205720687. The next prime is 205720721. The reversal of 205720720 is 27027502.

It can be written as a sum of positive squares in 2 ways, for example, as 103144336 + 102576384 = 10156^2 + 10128^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (205720721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1285675 + ... + 1285834.

It is an arithmetic number, because the mean of its divisors is an integer number (23915043).

Almost surely, 2^205720720 is an apocalyptic number.

205720720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

205720720 is an abundant number, since it is smaller than the sum of its proper divisors (272580140).

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

205720720 is a wasteful number, since it uses less digits than its factorization.

205720720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2571522 (or 2571516 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 25.

The square root of 205720720 is about 14342.9676148278. The cubic root of 205720720 is about 590.3270426614.

The spelling of 205720720 in words is "two hundred five million, seven hundred twenty thousand, seven hundred twenty".