6539721 has 8 divisors (see below), whose sum is σ = 8905344. Its totient is φ = 4266960.

The previous prime is 6539719. The next prime is 6539777. The reversal of 6539721 is 1279356.

6539721 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 6539721 - 2¹ = 6539719 is a prime.

It is a plaindrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (6549721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23050 + ... + 23331.

It is an arithmetic number, because the mean of its divisors is an integer number (1113168).

Almost surely, 2^6539721 is an apocalyptic number.

It is an amenable number.

6539721 is a deficient number, since it is larger than the sum of its proper divisors (2365623).

6539721 is a wasteful number, since it uses less digits than its factorization.

6539721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46431.

The product of its digits is 11340, while the sum is 33.

The square root of 6539721 is about 2557.2878211105. The cubic root of 6539721 is about 187.0049375764.

It can be divided in two parts, 6539 and 721, that added together give a triangular number (7260 = T₁₂₀).

The spelling of 6539721 in words is "six million, five hundred thirty-nine thousand, seven hundred twenty-one".