77920 has 24 divisors (see below), whose sum is σ = 184464. Its totient is φ = 31104.

The previous prime is 77899. The next prime is 77929. The reversal of 77920 is 2977.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 84 + ... + 403.

It is an arithmetic number, because the mean of its divisors is an integer number (7686).

2⁷⁷⁹²⁰ is an apocalyptic number.

It is an amenable number.

77920 is an abundant number, since it is smaller than the sum of its proper divisors (106544).

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 (92232).

77920 is a wasteful number, since it uses less digits than its factorization.

77920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 502 (or 494 counting only the distinct ones).

The product of its (nonzero) digits is 882, while the sum is 25.

The square root of 77920 is about 279.1415411579. The cubic root of 77920 is about 42.7119744400.

The spelling of 77920 in words is "seventy-seven thousand, nine hundred twenty".