6688978 has 8 divisors (see below), whose sum is σ = 10044540. Its totient is φ = 3340800.

The previous prime is 6688967. The next prime is 6688999. The reversal of 6688978 is 8798866.

It can be written as a sum of positive squares in 2 ways, for example, as 4652649 + 2036329 = 2157^2 + 1427^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2158 + ... + 4246.

Almost surely, 2^6688978 is an apocalyptic number.

6688978 is a deficient number, since it is larger than the sum of its proper divisors (3355562).

6688978 is a wasteful number, since it uses less digits than its factorization.

6688978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3692.

The product of its digits is 1161216, while the sum is 52.

The square root of 6688978 is about 2586.3058597157. The cubic root of 6688978 is about 188.4169296741.

The spelling of 6688978 in words is "six million, six hundred eighty-eight thousand, nine hundred seventy-eight".