6981691 has 4 divisors (see below), whose sum is σ = 6989032. Its totient is φ = 6974352.

The previous prime is 6981671. The next prime is 6981697. The reversal of 6981691 is 1961896.

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 not a de Polignac number, because 6981691 - 2⁵ = 6981659 is a prime.

It is a Duffinian number.

6981691 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (6981697) 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 in 3 ways as a sum of consecutive naturals, for example, 1986 + ... + 4231.

It is an arithmetic number, because the mean of its divisors is an integer number (1747258).

Almost surely, 2^6981691 is an apocalyptic number.

6981691 is a deficient number, since it is larger than the sum of its proper divisors (7341).

6981691 is a wasteful number, since it uses less digits than its factorization.

6981691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7340.

The product of its digits is 23328, while the sum is 40.

The square root of 6981691 is about 2642.2889698139. The cubic root of 6981691 is about 191.1261923855.

The spelling of 6981691 in words is "six million, nine hundred eighty-one thousand, six hundred ninety-one".