6991181 has 4 divisors (see below), whose sum is σ = 6998652. Its totient is φ = 6983712.

The previous prime is 6991147. The next prime is 6991253. The reversal of 6991181 is 1811996.

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 can be written as a sum of positive squares in 2 ways, for example, as 3960100 + 3031081 = 1990^2 + 1741^2 .

It is a cyclic number.

It is not a de Polignac number, because 6991181 - 2²² = 2796877 is a prime.

It is a super-2 number, since 2×6991181² = 97753223549522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6991111) 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 3 ways as a sum of consecutive naturals, for example, 2090 + ... + 4283.

It is an arithmetic number, because the mean of its divisors is an integer number (1749663).

Almost surely, 2^6991181 is an apocalyptic number.

It is an amenable number.

6991181 is a deficient number, since it is larger than the sum of its proper divisors (7471).

6991181 is a wasteful number, since it uses less digits than its factorization.

6991181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7470.

The product of its digits is 3888, while the sum is 35.

The square root of 6991181 is about 2644.0841514596. The cubic root of 6991181 is about 191.2127505167.

The spelling of 6991181 in words is "six million, nine hundred ninety-one thousand, one hundred eighty-one".