21213600125605 has 4 divisors (see below), whose sum is σ = 25456320150732. Its totient is φ = 16970880100480.

The previous prime is 21213600125591. The next prime is 21213600125609. The reversal of 21213600125605 is 50652100631212.

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 8894047679521 + 12319552446084 = 2982289^2 + 3509922^2 .

It is not a de Polignac number, because 21213600125605 - 2³⁵ = 21179240387237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213600125609) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2121360012556 + ... + 2121360012565.

It is an arithmetic number, because the mean of its divisors is an integer number (6364080037683).

Almost surely, 2^{21213600125605} is an apocalyptic number.

It is an amenable number.

21213600125605 is a deficient number, since it is larger than the sum of its proper divisors (4242720025127).

21213600125605 is an equidigital number, since it uses as much as digits as its factorization.

21213600125605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4242720025126.

The product of its (nonzero) digits is 21600, while the sum is 34.

Adding to 21213600125605 its reverse (50652100631212), we get a palindrome (71865700756817).

The spelling of 21213600125605 in words is "twenty-one trillion, two hundred thirteen billion, six hundred million, one hundred twenty-five thousand, six hundred five".