6821671 has 2 divisors, whose sum is σ = 6821672. Its totient is φ = 6821670.

The previous prime is 6821669. The next prime is 6821677. The reversal of 6821671 is 1761286.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6821671 - 2¹ = 6821669 is a prime.

Together with 6821669, it forms a pair of twin primes.

It is an Ulam number.

6821671 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6821677) 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, 3410835 + 3410836.

It is an arithmetic number, because the mean of its divisors is an integer number (3410836).

Almost surely, 2^6821671 is an apocalyptic number.

6821671 is a deficient number, since it is larger than the sum of its proper divisors (1).

6821671 is an equidigital number, since it uses as much as digits as its factorization.

6821671 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 31.

The square root of 6821671 is about 2611.8328813307. The cubic root of 6821671 is about 189.6546913711.

The spelling of 6821671 in words is "six million, eight hundred twenty-one thousand, six hundred seventy-one".