21040120324205 has 4 divisors (see below), whose sum is σ = 25248144389052. Its totient is φ = 16832096259360.

The previous prime is 21040120324193. The next prime is 21040120324229. The reversal of 21040120324205 is 50242302104012.

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 4228332676681 + 16811787647524 = 2056291^2 + 4100218^2 .

It is not a de Polignac number, because 21040120324205 - 2⁶ = 21040120324141 is a prime.

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, 2104012032416 + ... + 2104012032425.

It is an arithmetic number, because the mean of its divisors is an integer number (6312036097263).

Almost surely, 2^{21040120324205} is an apocalyptic number.

It is an amenable number.

21040120324205 is a deficient number, since it is larger than the sum of its proper divisors (4208024064847).

21040120324205 is an equidigital number, since it uses as much as digits as its factorization.

21040120324205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4208024064846.

The product of its (nonzero) digits is 3840, while the sum is 26.

Adding to 21040120324205 its reverse (50242302104012), we get a palindrome (71282422428217).

The spelling of 21040120324205 in words is "twenty-one trillion, forty billion, one hundred twenty million, three hundred twenty-four thousand, two hundred five".