6801991 has 4 divisors (see below), whose sum is σ = 7773712. Its totient is φ = 5830272.

The previous prime is 6801983. The next prime is 6802001. The reversal of 6801991 is 1991086.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 6801991 - 2³ = 6801983 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 (6801961) 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, 485850 + ... + 485863.

It is an arithmetic number, because the mean of its divisors is an integer number (1943428).

Almost surely, 2^6801991 is an apocalyptic number.

6801991 is a deficient number, since it is larger than the sum of its proper divisors (971721).

6801991 is an equidigital number, since it uses as much as digits as its factorization.

6801991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 971720.

The product of its (nonzero) digits is 3888, while the sum is 34.

The square root of 6801991 is about 2608.0626909643. The cubic root of 6801991 is about 189.4721359374.

The spelling of 6801991 in words is "six million, eight hundred one thousand, nine hundred ninety-one".