21242104105 has 4 divisors (see below), whose sum is σ = 25490524932. Its totient is φ = 16993683280.

The previous prime is 21242104099. The next prime is 21242104109. The reversal of 21242104105 is 50140124212.

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 16577077504 + 4665026601 = 128752^2 + 68301^2 .

It is not a de Polignac number, because 21242104105 - 2¹³ = 21242095913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21242104109) 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, 2124210406 + ... + 2124210415.

It is an arithmetic number, because the mean of its divisors is an integer number (6372631233).

Almost surely, 2^21242104105 is an apocalyptic number.

It is an amenable number.

21242104105 is a deficient number, since it is larger than the sum of its proper divisors (4248420827).

21242104105 is an equidigital number, since it uses as much as digits as its factorization.

21242104105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4248420826.

The product of its (nonzero) digits is 640, while the sum is 22.

Adding to 21242104105 its reverse (50140124212), we get a palindrome (71382228317).

The spelling of 21242104105 in words is "twenty-one billion, two hundred forty-two million, one hundred four thousand, one hundred five".