6778821 has 16 divisors (see below), whose sum is σ = 10571264. Its totient is φ = 3783024.

The previous prime is 6778799. The next prime is 6778823. The reversal of 6778821 is 1288776.

It is not a de Polignac number, because 6778821 - 2¹¹ = 6776773 is a prime.

It is a Duffinian number.

6778821 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 6778821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6778823) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2851 + ... + 4656.

It is an arithmetic number, because the mean of its divisors is an integer number (660704).

Almost surely, 2^6778821 is an apocalyptic number.

It is an amenable number.

6778821 is a deficient number, since it is larger than the sum of its proper divisors (3792443).

6778821 is a wasteful number, since it uses less digits than its factorization.

6778821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7560.

The product of its digits is 37632, while the sum is 39.

The square root of 6778821 is about 2603.6169073041. The cubic root of 6778821 is about 189.2567547077.

The spelling of 6778821 in words is "six million, seven hundred seventy-eight thousand, eight hundred twenty-one".