6991887 has 8 divisors (see below), whose sum is σ = 10654336. Its totient is φ = 3995352.

The previous prime is 6991877. The next prime is 6991889. The reversal of 6991887 is 7881996.

It is a happy number.

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

It is not a de Polignac number, because 6991887 - 2⁶ = 6991823 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6991889) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 166453 + ... + 166494.

It is an arithmetic number, because the mean of its divisors is an integer number (1331792).

Almost surely, 2^6991887 is an apocalyptic number.

6991887 is a deficient number, since it is larger than the sum of its proper divisors (3662449).

6991887 is a wasteful number, since it uses less digits than its factorization.

6991887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332957.

The product of its digits is 217728, while the sum is 48.

The square root of 6991887 is about 2644.2176536738. The cubic root of 6991887 is about 191.2191867997.

The spelling of 6991887 in words is "six million, nine hundred ninety-one thousand, eight hundred eighty-seven".