6778665 has 24 divisors (see below), whose sum is σ = 12442248. Its totient is φ = 3402240.

The previous prime is 6778661. The next prime is 6778691. The reversal of 6778665 is 5668776.

6778665 = 488² + 489² + ... + 514².

It can be written as a sum of positive squares in 4 ways, for example, as 3549456 + 3229209 = 1884^2 + 1797^2 .

It is not a de Polignac number, because 6778665 - 2² = 6778661 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 6778665.

It is not an unprimeable number, because it can be changed into a prime (6778661) 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, 3666 + ... + 5195.

It is an arithmetic number, because the mean of its divisors is an integer number (518427).

Almost surely, 2^6778665 is an apocalyptic number.

It is an amenable number.

6778665 is a deficient number, since it is larger than the sum of its proper divisors (5663583).

6778665 is a wasteful number, since it uses less digits than its factorization.

6778665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8889 (or 8886 counting only the distinct ones).

The product of its digits is 423360, while the sum is 45.

The square root of 6778665 is about 2603.5869488074. The cubic root of 6778665 is about 189.2553029174.

The spelling of 6778665 in words is "six million, seven hundred seventy-eight thousand, six hundred sixty-five".