6840989 has 2 divisors, whose sum is σ = 6840990. Its totient is φ = 6840988.

The previous prime is 6840983. The next prime is 6840997. The reversal of 6840989 is 9890486.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5040025 + 1800964 = 2245^2 + 1342^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6840989 is a prime.

It is a Sophie Germain prime.

It is an Ulam number.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6840983) 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 as a sum of consecutive naturals, namely, 3420494 + 3420495.

It is an arithmetic number, because the mean of its divisors is an integer number (3420495).

Almost surely, 2^6840989 is an apocalyptic number.

It is an amenable number.

6840989 is a deficient number, since it is larger than the sum of its proper divisors (1).

6840989 is an equidigital number, since it uses as much as digits as its factorization.

6840989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 124416, while the sum is 44.

The square root of 6840989 is about 2615.5284360909. The cubic root of 6840989 is about 189.8335476637.

The spelling of 6840989 in words is "six million, eight hundred forty thousand, nine hundred eighty-nine".