777 has 8 divisors (see below), whose sum is σ = 1216. Its totient is φ = 432.

The previous prime is 773. The next prime is 787.

777 is nontrivially palindromic in base 6 and base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 777 - 2² = 773 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 37 = 777 / (7 + 7 + 7).

It is a nude number because it is divisible by every one of its digits.

It is a Duffinian number.

777 is a modest number, since divided by 77 gives 7 as remainder.

777 is a lucky number.

777 is a nontrivial repdigit in base 6 and base 10.

It is a plaindrome in base 6, base 10, base 13 and base 15.

It is a nialpdrome in base 6 and base 10.

It is a zygodrome in base 6 and base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (773) 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, 3 + ... + 39.

It is an arithmetic number, because the mean of its divisors is an integer number (152).

It is an amenable number.

777 is a deficient number, since it is larger than the sum of its proper divisors (439).

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

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

The sum of its prime factors is 47.

The product of its digits is 343, while the sum is 21.

The square root of 777 is about 27.8747197295. The cubic root of 777 is about 9.1933474276.

Subtracting from 777 its product of digits (343), we obtain a palindrome (434).

The spelling of 777 in words is "seven hundred seventy-seven", and thus it is an aban number, an iban number, and an oban number.