6781391 has 2 divisors, whose sum is σ = 6781392. Its totient is φ = 6781390.

The previous prime is 6781387. The next prime is 6781399. The reversal of 6781391 is 1931876.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6781391 - 2² = 6781387 is a prime.

It is a Chen prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6781399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3390695 + 3390696.

It is an arithmetic number, because the mean of its divisors is an integer number (3390696).

Almost surely, 2^6781391 is an apocalyptic number.

6781391 is a deficient number, since it is larger than the sum of its proper divisors (1).

6781391 is an equidigital number, since it uses as much as digits as its factorization.

6781391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 35.

The square root of 6781391 is about 2604.1104047256. The cubic root of 6781391 is about 189.2806688174.

The spelling of 6781391 in words is "six million, seven hundred eighty-one thousand, three hundred ninety-one".