2855566781 has 2 divisors, whose sum is σ = 2855566782. Its totient is φ = 2855566780.

The previous prime is 2855566717. The next prime is 2855566793. The reversal of 2855566781 is 1876655582.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2656474681 + 199092100 = 51541^2 + 14110^2 .

It is a cyclic number.

It is not a de Polignac number, because 2855566781 - 2⁶ = 2855566717 is a prime.

It is a super-2 number, since 2×2855566781² = 16308523281501403922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2855566481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1427783390 + 1427783391.

It is an arithmetic number, because the mean of its divisors is an integer number (1427783391).

Almost surely, 2^2855566781 is an apocalyptic number.

It is an amenable number.

2855566781 is a deficient number, since it is larger than the sum of its proper divisors (1).

2855566781 is an equidigital number, since it uses as much as digits as its factorization.

2855566781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032000, while the sum is 53.

The square root of 2855566781 is about 53437.5035064326. The cubic root of 2855566781 is about 1418.7224476242.

The spelling of 2855566781 in words is "two billion, eight hundred fifty-five million, five hundred sixty-six thousand, seven hundred eighty-one".