777780 has 72 divisors (see below), whose sum is σ = 2457000. Its totient is φ = 198912.

The previous prime is 777769. The next prime is 777781. The reversal of 777780 is 87777.

It can be written as a sum of positive squares in 4 ways, for example, as 10404 + 767376 = 102^2 + 876^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (777781) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5146 + ... + 5294.

It is an arithmetic number, because the mean of its divisors is an integer number (34125).

2⁷⁷⁷⁷⁸⁰ 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 777780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1228500).

777780 is an abundant number, since it is smaller than the sum of its proper divisors (1679220).

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

777780 is a wasteful number, since it uses less digits than its factorization.

777780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193 (or 188 counting only the distinct ones).

The product of its (nonzero) digits is 19208, while the sum is 36.

The square root of 777780 is about 881.9183635689. The cubic root of 777780 is about 91.9642267975.

The spelling of 777780 in words is "seven hundred seventy-seven thousand, seven hundred eighty".