2780565905 has 16 divisors (see below), whose sum is σ = 3598838544. Its totient is φ = 2050202880.

The previous prime is 2780565901. The next prime is 2780565941. The reversal of 2780565905 is 5095650872.

It can be written as a sum of positive squares in 8 ways, for example, as 150209536 + 2630356369 = 12256^2 + 51287^2 .

It is not a de Polignac number, because 2780565905 - 2² = 2780565901 is a prime.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2780565905.

It is not an unprimeable number, because it can be changed into a prime (2780565901) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10607 + ... + 75323.

It is an arithmetic number, because the mean of its divisors is an integer number (224927409).

Almost surely, 2^2780565905 is an apocalyptic number.

It is an amenable number.

2780565905 is a deficient number, since it is larger than the sum of its proper divisors (818272639).

2780565905 is a wasteful number, since it uses less digits than its factorization.

2780565905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65396.

The product of its (nonzero) digits is 756000, while the sum is 47.

The square root of 2780565905 is about 52731.0715328259. The cubic root of 2780565905 is about 1406.1912710815.

The spelling of 2780565905 in words is "two billion, seven hundred eighty million, five hundred sixty-five thousand, nine hundred five".