1205805680 has 40 divisors (see below), whose sum is σ = 2863156032. Its totient is φ = 472058624.

The previous prime is 1205805673. The next prime is 1205805701. The reversal of 1205805680 is 865085021.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 1205805680.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 156587 + ... + 164106.

Almost surely, 2^1205805680 is an apocalyptic number.

1205805680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1205805680 is an abundant number, since it is smaller than the sum of its proper divisors (1657350352).

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

1205805680 is a wasteful number, since it uses less digits than its factorization.

1205805680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320753 (or 320747 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 35.

The square root of 1205805680 is about 34724.7128137872. The cubic root of 1205805680 is about 1064.3695505286.

The spelling of 1205805680 in words is "one billion, two hundred five million, eight hundred five thousand, six hundred eighty".