6978509 has 4 divisors (see below), whose sum is σ = 6984000. Its totient is φ = 6973020.

The previous prime is 6978481. The next prime is 6978511. The reversal of 6978509 is 9058796.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 6978509 - 2⁸ = 6978253 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6978509.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6978709) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 254 + ... + 3744.

It is an arithmetic number, because the mean of its divisors is an integer number (1746000).

Almost surely, 2^6978509 is an apocalyptic number.

It is an amenable number.

6978509 is a deficient number, since it is larger than the sum of its proper divisors (5491).

6978509 is a wasteful number, since it uses less digits than its factorization.

6978509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5490.

The product of its (nonzero) digits is 136080, while the sum is 44.

The square root of 6978509 is about 2641.6867717426. The cubic root of 6978509 is about 191.0971518583.

The spelling of 6978509 in words is "six million, nine hundred seventy-eight thousand, five hundred nine".