6778421 has 12 divisors (see below), whose sum is σ = 7729920. Its totient is φ = 5924880.

The previous prime is 6778417. The next prime is 6778423. The reversal of 6778421 is 1248776.

It is a happy number.

6778421 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 6778421 - 2² = 6778417 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6778423) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2156 + ... + 4266.

It is an arithmetic number, because the mean of its divisors is an integer number (644160).

Almost surely, 2^6778421 is an apocalyptic number.

It is an amenable number.

6778421 is a deficient number, since it is larger than the sum of its proper divisors (951499).

6778421 is a wasteful number, since it uses less digits than its factorization.

6778421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2156 (or 2143 counting only the distinct ones).

The product of its digits is 18816, while the sum is 35.

The square root of 6778421 is about 2603.5400899544. The cubic root of 6778421 is about 189.2530321238.

The spelling of 6778421 in words is "six million, seven hundred seventy-eight thousand, four hundred twenty-one".