6821978 has 4 divisors (see below), whose sum is σ = 10232970. Its totient is φ = 3410988.

The previous prime is 6821963. The next prime is 6822017. The reversal of 6821978 is 8791286.

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

It can be written as a sum of positive squares in only one way, i.e., 6568969 + 253009 = 2563^2 + 503^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1705493 + ... + 1705496.

Almost surely, 2^6821978 is an apocalyptic number.

6821978 is a deficient number, since it is larger than the sum of its proper divisors (3410992).

6821978 is a wasteful number, since it uses less digits than its factorization.

6821978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3410991.

The product of its digits is 48384, while the sum is 41.

The square root of 6821978 is about 2611.8916516579. The cubic root of 6821978 is about 189.6575363786.

The spelling of 6821978 in words is "six million, eight hundred twenty-one thousand, nine hundred seventy-eight".