6991998 has 32 divisors (see below), whose sum is σ = 15948576. Its totient is φ = 2024448.

The previous prime is 6991997. The next prime is 6992039. The reversal of 6991998 is 8991996.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a self number, because there is not a number n which added to its sum of digits gives 6991998.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6991991) 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 15 ways as a sum of consecutive naturals, for example, 1311 + ... + 3962.

It is an arithmetic number, because the mean of its divisors is an integer number (498393).

Almost surely, 2^6991998 is an apocalyptic number.

6991998 is an abundant number, since it is smaller than the sum of its proper divisors (8956578).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6991998 is a wasteful number, since it uses less digits than its factorization.

6991998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5308.

The product of its digits is 314928, while the sum is 51.

The square root of 6991998 is about 2644.2386427855. The cubic root of 6991998 is about 191.2201986971.

The spelling of 6991998 in words is "six million, nine hundred ninety-one thousand, nine hundred ninety-eight".