6981209 has 4 divisors (see below), whose sum is σ = 7076916. Its totient is φ = 6885504.

The previous prime is 6981181. The next prime is 6981211. The reversal of 6981209 is 9021896.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2371600 + 4609609 = 1540^2 + 2147^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6981209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6981229) 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 3 ways as a sum of consecutive naturals, for example, 47744 + ... + 47889.

It is an arithmetic number, because the mean of its divisors is an integer number (1769229).

Almost surely, 2^6981209 is an apocalyptic number.

It is an amenable number.

6981209 is a deficient number, since it is larger than the sum of its proper divisors (95707).

6981209 is an equidigital number, since it uses as much as digits as its factorization.

6981209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95706.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 6981209 is about 2642.1977594419. The cubic root of 6981209 is about 191.1217939790.

The spelling of 6981209 in words is "six million, nine hundred eighty-one thousand, two hundred nine".