6819661 has 4 divisors (see below), whose sum is σ = 7116192. Its totient is φ = 6523132.

The previous prime is 6819649. The next prime is 6819667. The reversal of 6819661 is 1669186.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1669186 = 2 ⋅834593.

It is a cyclic number.

It is not a de Polignac number, because 6819661 - 2⁵ = 6819629 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6819661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6819667) 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 3 ways as a sum of consecutive naturals, for example, 148231 + ... + 148276.

It is an arithmetic number, because the mean of its divisors is an integer number (1779048).

Almost surely, 2^6819661 is an apocalyptic number.

It is an amenable number.

6819661 is a deficient number, since it is larger than the sum of its proper divisors (296531).

6819661 is a wasteful number, since it uses less digits than its factorization.

6819661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296530.

The product of its digits is 15552, while the sum is 37.

The square root of 6819661 is about 2611.4480657291. The cubic root of 6819661 is about 189.6360623393.

The spelling of 6819661 in words is "six million, eight hundred nineteen thousand, six hundred sixty-one".