6991985 has 48 divisors (see below), whose sum is σ = 11440128. Its totient is φ = 3991680.

The previous prime is 6991979. The next prime is 6991991. The reversal of 6991985 is 5891996.

It is an interprime number because it is at equal distance from previous prime (6991979) and next prime (6991991).

It is not a de Polignac number, because 6991985 - 2⁴ = 6991969 is a prime.

It is a Curzon number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 54992 + ... + 55118.

It is an arithmetic number, because the mean of its divisors is an integer number (238336).

Almost surely, 2^6991985 is an apocalyptic number.

6991985 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

6991985 is a deficient number, since it is larger than the sum of its proper divisors (4448143).

6991985 is a wasteful number, since it uses less digits than its factorization.

6991985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174 (or 163 counting only the distinct ones).

The product of its digits is 174960, while the sum is 47.

The square root of 6991985 is about 2644.2361846098. The cubic root of 6991985 is about 191.2200801871.

The spelling of 6991985 in words is "six million, nine hundred ninety-one thousand, nine hundred eighty-five".