77720 has 32 divisors (see below), whose sum is σ = 183600. Its totient is φ = 29568.

The previous prime is 77719. The next prime is 77723. The reversal of 77720 is 2777.

77720 is nontrivially palindromic in base 11.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1127 + ... + 1193.

2⁷⁷⁷²⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91800).

77720 is an abundant number, since it is smaller than the sum of its proper divisors (105880).

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

77720 is a wasteful number, since it uses less digits than its factorization.

77720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107 (or 103 counting only the distinct ones).

The product of its (nonzero) digits is 686, while the sum is 23.

The square root of 77720 is about 278.7830697872. The cubic root of 77720 is about 42.6753996881.

It can be divided in two parts, 777 and 20, that added together give a palindrome (797).

The spelling of 77720 in words is "seventy-seven thousand, seven hundred twenty", and thus it is an iban number.