6541323721 has 8 divisors (see below), whose sum is σ = 6881974344. Its totient is φ = 6209297280.

The previous prime is 6541323709. The next prime is 6541323731. The reversal of 6541323721 is 1273231456.

It can be written as a sum of positive squares in 4 ways, for example, as 2822400 + 6538501321 = 1680^2 + 80861^2 .

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 6541323721 - 2⁵ = 6541323689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6541323731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2154490 + ... + 2157523.

It is an arithmetic number, because the mean of its divisors is an integer number (860246793).

Almost surely, 2^6541323721 is an apocalyptic number.

It is an amenable number.

6541323721 is a deficient number, since it is larger than the sum of its proper divisors (340650623).

6541323721 is a wasteful number, since it uses less digits than its factorization.

6541323721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4312091.

The product of its digits is 30240, while the sum is 34.

The square root of 6541323721 is about 80878.4502880712. The cubic root of 6541323721 is about 1870.2021306286.

The spelling of 6541323721 in words is "six billion, five hundred forty-one million, three hundred twenty-three thousand, seven hundred twenty-one".