6684021 has 12 divisors (see below), whose sum is σ = 9677772. Its totient is φ = 4445376.

The previous prime is 6684019. The next prime is 6684023. The reversal of 6684021 is 1204866.

It is an interprime number because it is at equal distance from previous prime (6684019) and next prime (6684023).

It can be written as a sum of positive squares in 2 ways, for example, as 4901796 + 1782225 = 2214^2 + 1335^2 .

It is not a de Polignac number, because 6684021 - 2¹ = 6684019 is a prime.

It is a super-2 number, since 2×6684021² = 89352273456882, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6684023) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5545 + ... + 6641.

It is an arithmetic number, because the mean of its divisors is an integer number (806481).

Almost surely, 2^6684021 is an apocalyptic number.

It is an amenable number.

6684021 is a deficient number, since it is larger than the sum of its proper divisors (2993751).

6684021 is a wasteful number, since it uses less digits than its factorization.

6684021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1780 (or 1777 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 6684021 is about 2585.3473654424. The cubic root of 6684021 is about 188.3703748028.

Adding to 6684021 its reverse (1204866), we get a palindrome (7888887).

The spelling of 6684021 in words is "six million, six hundred eighty-four thousand, twenty-one".