6891978 has 8 divisors (see below), whose sum is σ = 13783968. Its totient is φ = 2297324.

The previous prime is 6891971. The next prime is 6891979. The reversal of 6891978 is 8791986.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

6891978 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (6891971) 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, 574326 + ... + 574337.

It is an arithmetic number, because the mean of its divisors is an integer number (1722996).

Almost surely, 2^6891978 is an apocalyptic number.

6891978 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6891978 is a wasteful number, since it uses less digits than its factorization.

6891978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1148668.

The product of its digits is 217728, while the sum is 48.

The square root of 6891978 is about 2625.2577016362. The cubic root of 6891978 is about 190.3040192807.

The spelling of 6891978 in words is "six million, eight hundred ninety-one thousand, nine hundred seventy-eight".