6981991 has 8 divisors (see below), whose sum is σ = 7185600. Its totient is φ = 6780768.

The previous prime is 6981983. The next prime is 6982009. The reversal of 6981991 is 1991896.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6981991 - 2³ = 6981983 is a prime.

It is a Duffinian number.

6981991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6981391) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6505 + ... + 7501.

It is an arithmetic number, because the mean of its divisors is an integer number (898200).

Almost surely, 2^6981991 is an apocalyptic number.

6981991 is a deficient number, since it is larger than the sum of its proper divisors (203609).

6981991 is a wasteful number, since it uses less digits than its factorization.

6981991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1193.

The product of its digits is 34992, while the sum is 43.

The square root of 6981991 is about 2642.3457381652. The cubic root of 6981991 is about 191.1289298806.

The spelling of 6981991 in words is "six million, nine hundred eighty-one thousand, nine hundred ninety-one".