21210100421305 has 4 divisors (see below), whose sum is σ = 25452120505572. Its totient is φ = 16968080337040.

The previous prime is 21210100421299. The next prime is 21210100421357. The reversal of 21210100421305 is 50312400101212.

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 6605557936384 + 14604542484921 = 2570128^2 + 3821589^2 .

It is not a de Polignac number, because 21210100421305 - 2¹⁹ = 21210099897017 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2121010042126 + ... + 2121010042135.

It is an arithmetic number, because the mean of its divisors is an integer number (6363030126393).

Almost surely, 2^{21210100421305} is an apocalyptic number.

It is an amenable number.

21210100421305 is a deficient number, since it is larger than the sum of its proper divisors (4242020084267).

21210100421305 is an equidigital number, since it uses as much as digits as its factorization.

21210100421305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4242020084266.

The product of its (nonzero) digits is 480, while the sum is 22.

Adding to 21210100421305 its reverse (50312400101212), we get a palindrome (71522500522517).

The spelling of 21210100421305 in words is "twenty-one trillion, two hundred ten billion, one hundred million, four hundred twenty-one thousand, three hundred five".