6685391 has 2 divisors, whose sum is σ = 6685392. Its totient is φ = 6685390.

The previous prime is 6685379. The next prime is 6685409. The reversal of 6685391 is 1935866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6685391 - 2¹⁴ = 6669007 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6685331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3342695 + 3342696.

It is an arithmetic number, because the mean of its divisors is an integer number (3342696).

Almost surely, 2^6685391 is an apocalyptic number.

6685391 is a deficient number, since it is larger than the sum of its proper divisors (1).

6685391 is an equidigital number, since it uses as much as digits as its factorization.

6685391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 38.

The square root of 6685391 is about 2585.6123065920. The cubic root of 6685391 is about 188.3832437920.

The spelling of 6685391 in words is "six million, six hundred eighty-five thousand, three hundred ninety-one".