6781979 has 4 divisors (see below), whose sum is σ = 6787320. Its totient is φ = 6776640.

The previous prime is 6781967. The next prime is 6782021. The reversal of 6781979 is 9791876.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6781979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6781939) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 452 + ... + 3710.

It is an arithmetic number, because the mean of its divisors is an integer number (1696830).

Almost surely, 2^6781979 is an apocalyptic number.

6781979 is a deficient number, since it is larger than the sum of its proper divisors (5341).

6781979 is a wasteful number, since it uses less digits than its factorization.

6781979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5340.

The product of its digits is 190512, while the sum is 47.

The square root of 6781979 is about 2604.2233007175. The cubic root of 6781979 is about 189.2861393674.

The spelling of 6781979 in words is "six million, seven hundred eighty-one thousand, nine hundred seventy-nine".