21500553113005 has 4 divisors (see below), whose sum is σ = 25800663735612. Its totient is φ = 17200442490400.

The previous prime is 21500553112967. The next prime is 21500553113059. The reversal of 21500553113005 is 50031135500512.

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 10394936877924 + 11105616235081 = 3224118^2 + 3332509^2 .

It is not a de Polignac number, because 21500553113005 - 2⁴³ = 12704460090797 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2150055311296 + ... + 2150055311305.

It is an arithmetic number, because the mean of its divisors is an integer number (6450165933903).

Almost surely, 2^{21500553113005} is an apocalyptic number.

It is an amenable number.

21500553113005 is a deficient number, since it is larger than the sum of its proper divisors (4300110622607).

21500553113005 is an equidigital number, since it uses as much as digits as its factorization.

21500553113005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4300110622606.

The product of its (nonzero) digits is 11250, while the sum is 31.

Adding to 21500553113005 its reverse (50031135500512), we get a palindrome (71531688613517).

The spelling of 21500553113005 in words is "twenty-one trillion, five hundred billion, five hundred fifty-three million, one hundred thirteen thousand, five".