6991389 has 12 divisors (see below), whose sum is σ = 10289916. Its totient is φ = 4572672.

The previous prime is 6991381. The next prime is 6991417. The reversal of 6991389 is 9831996.

It can be written as a sum of positive squares in 2 ways, for example, as 6335289 + 656100 = 2517^2 + 810^2 .

It is not a de Polignac number, because 6991389 - 2³ = 6991381 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6991381) 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 11 ways as a sum of consecutive naturals, for example, 6852 + ... + 7805.

It is an arithmetic number, because the mean of its divisors is an integer number (857493).

Almost surely, 2^6991389 is an apocalyptic number.

It is an amenable number.

6991389 is a deficient number, since it is larger than the sum of its proper divisors (3298527).

6991389 is a wasteful number, since it uses less digits than its factorization.

6991389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14716 (or 14713 counting only the distinct ones).

The product of its digits is 104976, while the sum is 45.

The square root of 6991389 is about 2644.1234842571. The cubic root of 6991389 is about 191.2146468037.

The spelling of 6991389 in words is "six million, nine hundred ninety-one thousand, three hundred eighty-nine".