77939693977 has 4 divisors (see below), whose sum is σ = 82524381876. Its totient is φ = 73355006080.

The previous prime is 77939693971. The next prime is 77939694031.

77939693977 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 23640907536 + 54298786441 = 153756^2 + 233021^2 .

It is a cyclic number.

It is not a de Polignac number, because 77939693977 - 2¹⁵ = 77939661209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77939693971) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2292343924 + ... + 2292343957.

It is an arithmetic number, because the mean of its divisors is an integer number (20631095469).

Almost surely, 2^77939693977 is an apocalyptic number.

It is an amenable number.

77939693977 is a deficient number, since it is larger than the sum of its proper divisors (4584687899).

77939693977 is a wasteful number, since it uses less digits than its factorization.

77939693977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4584687898.

The product of its digits is 850659894, while the sum is 76.

The spelling of 77939693977 in words is "seventy-seven billion, nine hundred thirty-nine million, six hundred ninety-three thousand, nine hundred seventy-seven".