77981618977 has 2 divisors, whose sum is σ = 77981618978. Its totient is φ = 77981618976.

The previous prime is 77981618839. The next prime is 77981619019.

77981618977 is nontrivially palindromic in base 10.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55582306081 + 22399312896 = 235759^2 + 149664^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 77981618977 - 2³¹ = 75834135329 is a prime.

It is a super-2 number, since 2×77981618977² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (77981618177) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38990809488 + 38990809489.

It is an arithmetic number, because the mean of its divisors is an integer number (38990809489).

Almost surely, 2^77981618977 is an apocalyptic number.

It is an amenable number.

77981618977 is a deficient number, since it is larger than the sum of its proper divisors (1).

77981618977 is an equidigital number, since it uses as much as digits as its factorization.

77981618977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 74680704, while the sum is 70.

The spelling of 77981618977 in words is "seventy-seven billion, nine hundred eighty-one million, six hundred eighteen thousand, nine hundred seventy-seven".