77477447681 has 2 divisors, whose sum is σ = 77477447682. Its totient is φ = 77477447680.

The previous prime is 77477447669. The next prime is 77477447689. The reversal of 77477447681 is 18674477477.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51195850225 + 26281597456 = 226265^2 + 162116^2 .

It is a cyclic number.

It is not a de Polignac number, because 77477447681 - 2¹⁸ = 77477185537 is a prime.

It is a super-2 number, since 2×77477447681² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (77477447689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38738723840 + 38738723841.

It is an arithmetic number, because the mean of its divisors is an integer number (38738723841).

Almost surely, 2^77477447681 is an apocalyptic number.

It is an amenable number.

77477447681 is a deficient number, since it is larger than the sum of its proper divisors (1).

77477447681 is an equidigital number, since it uses as much as digits as its factorization.

77477447681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51631104, while the sum is 62.

The spelling of 77477447681 in words is "seventy-seven billion, four hundred seventy-seven million, four hundred forty-seven thousand, six hundred eighty-one".