77680 has 20 divisors (see below), whose sum is σ = 180792. Its totient is φ = 31040.

The previous prime is 77659. The next prime is 77681. The reversal of 77680 is 8677.

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77681) 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, 406 + ... + 565.

2⁷⁷⁶⁸⁰ is an apocalyptic number.

It is an amenable number.

77680 is an abundant number, since it is smaller than the sum of its proper divisors (103112).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90396).

77680 is a wasteful number, since it uses less digits than its factorization.

77680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 984 (or 978 counting only the distinct ones).

The product of its (nonzero) digits is 2352, while the sum is 28.

The square root of 77680 is about 278.7113201863. The cubic root of 77680 is about 42.6680772103.

It can be divided in two parts, 77 and 680, that added together give a palindrome (757).

The spelling of 77680 in words is "seventy-seven thousand, six hundred eighty".