77790 has 16 divisors (see below), whose sum is σ = 186768. Its totient is φ = 20736.

The previous prime is 77783. The next prime is 77797. The reversal of 77790 is 9777.

It is an interprime number because it is at equal distance from previous prime (77783) and next prime (77797).

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 2593 = 77790 / (7 + 7 + 7 + 9 + 0).

It is a Curzon 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.

77790 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1267 + ... + 1326.

It is an arithmetic number, because the mean of its divisors is an integer number (11673).

2⁷⁷⁷⁹⁰ is an apocalyptic number.

77790 is an abundant number, since it is smaller than the sum of its proper divisors (108978).

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 (93384).

77790 is a wasteful number, since it uses less digits than its factorization.

77790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2603.

The product of its (nonzero) digits is 3087, while the sum is 30.

The square root of 77790 is about 278.9085871751. The cubic root of 77790 is about 42.6882079810.

The spelling of 77790 in words is "seventy-seven thousand, seven hundred ninety".