6789721 has 4 divisors (see below), whose sum is σ = 6866100. Its totient is φ = 6713344.

The previous prime is 6789701. The next prime is 6789737. The reversal of 6789721 is 1279876.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 855625 + 5934096 = 925^2 + 2436^2 .

It is a cyclic number.

It is not a de Polignac number, because 6789721 - 2¹⁷ = 6658649 is a prime.

It is a super-2 number, since 2×6789721² = 92200622515682, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

6789721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (6789701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38056 + ... + 38233.

It is an arithmetic number, because the mean of its divisors is an integer number (1716525).

Almost surely, 2^6789721 is an apocalyptic number.

It is an amenable number.

6789721 is a deficient number, since it is larger than the sum of its proper divisors (76379).

6789721 is an equidigital number, since it uses as much as digits as its factorization.

6789721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76378.

The product of its digits is 42336, while the sum is 40.

The square root of 6789721 is about 2605.7093084226. The cubic root of 6789721 is about 189.3581388046.

The spelling of 6789721 in words is "six million, seven hundred eighty-nine thousand, seven hundred twenty-one".