6991091 has 2 divisors, whose sum is σ = 6991092. Its totient is φ = 6991090.

The previous prime is 6991043. The next prime is 6991093. The reversal of 6991091 is 1901996.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6991091 - 2¹⁸ = 6728947 is a prime.

Together with 6991093, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (6991093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3495545 + 3495546.

It is an arithmetic number, because the mean of its divisors is an integer number (3495546).

Almost surely, 2^6991091 is an apocalyptic number.

6991091 is a deficient number, since it is larger than the sum of its proper divisors (1).

6991091 is an equidigital number, since it uses as much as digits as its factorization.

6991091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4374, while the sum is 35.

The square root of 6991091 is about 2644.0671322794. The cubic root of 6991091 is about 191.2119299962.

The spelling of 6991091 in words is "six million, nine hundred ninety-one thousand, ninety-one".