77993578655 has 4 divisors (see below), whose sum is σ = 93592294392. Its totient is φ = 62394862920.

The previous prime is 77993578643. The next prime is 77993578679. The reversal of 77993578655 is 55687539977.

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

It is not a de Polignac number, because 77993578655 - 2²⁶ = 77926469791 is a prime.

It is a super-2 number, since 2×77993578655² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 7799357861 + ... + 7799357870.

It is an arithmetic number, because the mean of its divisors is an integer number (23398073598).

Almost surely, 2^77993578655 is an apocalyptic number.

77993578655 is a deficient number, since it is larger than the sum of its proper divisors (15598715737).

77993578655 is a wasteful number, since it uses less digits than its factorization.

77993578655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15598715736.

The product of its digits is 500094000, while the sum is 71.

The spelling of 77993578655 in words is "seventy-seven billion, nine hundred ninety-three million, five hundred seventy-eight thousand, six hundred fifty-five".