21520540042005 has 32 divisors (see below), whose sum is σ = 34492339880064. Its totient is φ = 11457797677056.

The previous prime is 21520540041943. The next prime is 21520540042021. The reversal of 21520540042005 is 50024004502512.

It is not a de Polignac number, because 21520540042005 - 2¹⁵ = 21520540009237 is a prime.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 393638682 + ... + 393693348.

It is an arithmetic number, because the mean of its divisors is an integer number (1077885621252).

Almost surely, 2^{21520540042005} is an apocalyptic number.

It is an amenable number.

21520540042005 is a deficient number, since it is larger than the sum of its proper divisors (12971799838059).

21520540042005 is a wasteful number, since it uses less digits than its factorization.

21520540042005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99525.

The product of its (nonzero) digits is 16000, while the sum is 30.

Adding to 21520540042005 its reverse (50024004502512), we get a palindrome (71544544544517).

The spelling of 21520540042005 in words is "twenty-one trillion, five hundred twenty billion, five hundred forty million, forty-two thousand, five".