2785755781 has 2 divisors, whose sum is σ = 2785755782. Its totient is φ = 2785755780.

The previous prime is 2785755733. The next prime is 2785755793. The reversal of 2785755781 is 1875575872.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2641034881 + 144720900 = 51391^2 + 12030^2 .

It is a cyclic number.

It is not a de Polignac number, because 2785755781 - 2¹³ = 2785747589 is a prime.

It is a super-2 number, since 2×2785755781² = 15520870542749839922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2785705781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1392877890 + 1392877891.

It is an arithmetic number, because the mean of its divisors is an integer number (1392877891).

Almost surely, 2^2785755781 is an apocalyptic number.

It is an amenable number.

2785755781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2785755781 is an equidigital number, since it uses as much as digits as its factorization.

2785755781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5488000, while the sum is 55.

The square root of 2785755781 is about 52780.2593873884. The cubic root of 2785755781 is about 1407.0656041943.

It can be divided in two parts, 27857 and 55781, that added together give a palindrome (83638).

The spelling of 2785755781 in words is "two billion, seven hundred eighty-five million, seven hundred fifty-five thousand, seven hundred eighty-one".