21504123241 has 4 divisors (see below), whose sum is σ = 21504916692. Its totient is φ = 21503329792.

The previous prime is 21504123163. The next prime is 21504123253. The reversal of 21504123241 is 14232140512.

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 1821155625 + 19682967616 = 42675^2 + 140296^2 .

It is a cyclic number.

It is not a de Polignac number, because 21504123241 - 2⁹ = 21504122729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21504123281) 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 3 ways as a sum of consecutive naturals, for example, 354580 + ... + 410773.

It is an arithmetic number, because the mean of its divisors is an integer number (5376229173).

Almost surely, 2^21504123241 is an apocalyptic number.

It is an amenable number.

21504123241 is a deficient number, since it is larger than the sum of its proper divisors (793451).

21504123241 is an equidigital number, since it uses as much as digits as its factorization.

21504123241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 793450.

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 21504123241 its reverse (14232140512), we get a palindrome (35736263753).

The spelling of 21504123241 in words is "twenty-one billion, five hundred four million, one hundred twenty-three thousand, two hundred forty-one".