6820021 has 8 divisors (see below), whose sum is σ = 7413560. Its totient is φ = 6236352.

The previous prime is 6820019. The next prime is 6820039. The reversal of 6820021 is 1200286.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1179396 + 5640625 = 1086^2 + 2375^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 6820021 - 2¹ = 6820019 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6820001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 990 + ... + 3823.

It is an arithmetic number, because the mean of its divisors is an integer number (926695).

Almost surely, 2^6820021 is an apocalyptic number.

It is an amenable number.

6820021 is a deficient number, since it is larger than the sum of its proper divisors (593539).

6820021 is a wasteful number, since it uses less digits than its factorization.

6820021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4935.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 6820021 is about 2611.5169920948. The cubic root of 6820021 is about 189.6393991514.

The spelling of 6820021 in words is "six million, eight hundred twenty thousand, twenty-one".