6888991 has 4 divisors (see below), whose sum is σ = 6909192. Its totient is φ = 6868792.

The previous prime is 6888989. The next prime is 6888997. The reversal of 6888991 is 1998886.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 6888991 - 2¹ = 6888989 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 (6888997) 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, 9580 + ... + 10273.

It is an arithmetic number, because the mean of its divisors is an integer number (1727298).

Almost surely, 2^6888991 is an apocalyptic number.

6888991 is a deficient number, since it is larger than the sum of its proper divisors (20201).

6888991 is a wasteful number, since it uses less digits than its factorization.

6888991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20200.

The product of its digits is 248832, while the sum is 49.

The square root of 6888991 is about 2624.6887434513. The cubic root of 6888991 is about 190.2765225666.

It can be divided in two parts, 688899 and 1, that added together give a square (688900 = 830²).

The spelling of 6888991 in words is "six million, eight hundred eighty-eight thousand, nine hundred ninety-one".