776881681 has 2 divisors, whose sum is σ = 776881682. Its totient is φ = 776881680.

The previous prime is 776881643. The next prime is 776881751. The reversal of 776881681 is 186188677.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 608115600 + 168766081 = 24660^2 + 12991^2 .

It is a cyclic number.

It is not a de Polignac number, because 776881681 - 2⁹ = 776881169 is a prime.

It is a super-2 number, since 2×776881681² = 1207090292546771522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (776881601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 388440840 + 388440841.

It is an arithmetic number, because the mean of its divisors is an integer number (388440841).

Almost surely, 2^776881681 is an apocalyptic number.

It is an amenable number.

776881681 is a deficient number, since it is larger than the sum of its proper divisors (1).

776881681 is an equidigital number, since it uses as much as digits as its factorization.

776881681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 903168, while the sum is 52.

The square root of 776881681 is about 27872.5973134905. The cubic root of 776881681 is about 919.2880759664.

The spelling of 776881681 in words is "seven hundred seventy-six million, eight hundred eighty-one thousand, six hundred eighty-one".