77918681977 has 8 divisors (see below), whose sum is σ = 82586595816. Its totient is φ = 73260152832.

The previous prime is 77918681947. The next prime is 77918682007.

77918681977 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (77918681947) and next prime (77918682007).

It can be written as a sum of positive squares in 4 ways, for example, as 34214270841 + 43704411136 = 184971^2 + 209056^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 77918681977 - 2¹¹ = 77918679929 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77918681927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2329068 + ... + 2362285.

It is an arithmetic number, because the mean of its divisors is an integer number (10323324477).

Almost surely, 2^77918681977 is an apocalyptic number.

It is an amenable number.

77918681977 is a deficient number, since it is larger than the sum of its proper divisors (4667913839).

77918681977 is a wasteful number, since it uses less digits than its factorization.

77918681977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4692347.

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

The spelling of 77918681977 in words is "seventy-seven billion, nine hundred eighteen million, six hundred eighty-one thousand, nine hundred seventy-seven".