77791 has 4 divisors (see below), whose sum is σ = 88912. Its totient is φ = 66672.

The previous prime is 77783. The next prime is 77797. The reversal of 77791 is 19777.

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

It is a cyclic number.

It is not a de Polignac number, because 77791 - 2³ = 77783 is a prime.

It is a Duffinian number.

77791 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77797) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5550 + ... + 5563.

It is an arithmetic number, because the mean of its divisors is an integer number (22228).

2⁷⁷⁷⁹¹ is an apocalyptic number.

77791 is a deficient number, since it is larger than the sum of its proper divisors (11121).

77791 is a wasteful number, since it uses less digits than its factorization.

77791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11120.

The product of its digits is 3087, while the sum is 31.

The square root of 77791 is about 278.9103798714. The cubic root of 77791 is about 42.6883909009.

It can be divided in two parts, 777 and 91, that multiplied together give a palindrome (70707).

The spelling of 77791 in words is "seventy-seven thousand, seven hundred ninety-one".