6691021 has 8 divisors (see below), whose sum is σ = 7080800. Its totient is φ = 6305040.

The previous prime is 6691019. The next prime is 6691037. The reversal of 6691021 is 1201966.

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 6691021 - 2¹ = 6691019 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 (6691051) 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 in 7 ways as a sum of consecutive naturals, for example, 3175 + ... + 4843.

It is an arithmetic number, because the mean of its divisors is an integer number (885100).

Almost surely, 2^6691021 is an apocalyptic number.

It is an amenable number.

6691021 is a deficient number, since it is larger than the sum of its proper divisors (389779).

6691021 is a wasteful number, since it uses less digits than its factorization.

6691021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1899.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 6691021 is about 2586.7007944484. The cubic root of 6691021 is about 188.4361103125.

Adding to 6691021 its reverse (1201966), we get a palindrome (7892987).

The spelling of 6691021 in words is "six million, six hundred ninety-one thousand, twenty-one".