76777765681 has 2 divisors, whose sum is σ = 76777765682. Its totient is φ = 76777765680.

The previous prime is 76777765679. The next prime is 76777765693. The reversal of 76777765681 is 18656777767.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55105215025 + 21672550656 = 234745^2 + 147216^2 .

It is an emirp because it is prime and its reverse (18656777767) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 76777765681 - 2¹ = 76777765679 is a prime.

It is a super-2 number, since 2×76777765681² (a number of 23 digits) contains 22 as substring.

Together with 76777765679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (76177765681) 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, 38388882840 + 38388882841.

It is an arithmetic number, because the mean of its divisors is an integer number (38388882841).

Almost surely, 2^76777765681 is an apocalyptic number.

It is an amenable number.

76777765681 is a deficient number, since it is larger than the sum of its proper divisors (1).

76777765681 is an equidigital number, since it uses as much as digits as its factorization.

76777765681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145212480, while the sum is 67.

The spelling of 76777765681 in words is "seventy-six billion, seven hundred seventy-seven million, seven hundred sixty-five thousand, six hundred eighty-one".