6691391 has 6 divisors (see below), whose sum is σ = 7783920. Its totient is φ = 5735436.

The previous prime is 6691369. The next prime is 6691397. The reversal of 6691391 is 1931966.

It is not a de Polignac number, because 6691391 - 2¹⁴ = 6675007 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 (6691397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 68231 + ... + 68328.

It is an arithmetic number, because the mean of its divisors is an integer number (1297320).

Almost surely, 2^6691391 is an apocalyptic number.

6691391 is a deficient number, since it is larger than the sum of its proper divisors (1092529).

6691391 is a wasteful number, since it uses less digits than its factorization.

6691391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136573 (or 136566 counting only the distinct ones).

The product of its digits is 8748, while the sum is 35.

The square root of 6691391 is about 2586.7723131347. The cubic root of 6691391 is about 188.4395836277.

The spelling of 6691391 in words is "six million, six hundred ninety-one thousand, three hundred ninety-one".