6481721 has 4 divisors (see below), whose sum is σ = 6494244. Its totient is φ = 6469200.

The previous prime is 6481711. The next prime is 6481729. The reversal of 6481721 is 1271846.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1271846 = 2 ⋅635923.

It can be written as a sum of positive squares in 2 ways, for example, as 4791721 + 1690000 = 2189^2 + 1300^2 .

It is a cyclic number.

It is not a de Polignac number, because 6481721 - 2¹⁰ = 6480697 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6481729) 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, 5450 + ... + 6531.

It is an arithmetic number, because the mean of its divisors is an integer number (1623561).

Almost surely, 2^6481721 is an apocalyptic number.

It is an amenable number.

6481721 is a deficient number, since it is larger than the sum of its proper divisors (12523).

6481721 is a wasteful number, since it uses less digits than its factorization.

6481721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12522.

The product of its digits is 2688, while the sum is 29.

The square root of 6481721 is about 2545.9224261552. The cubic root of 6481721 is about 186.4504536714.

The spelling of 6481721 in words is "six million, four hundred eighty-one thousand, seven hundred twenty-one".