21535243105 has 4 divisors (see below), whose sum is σ = 25842291732. Its totient is φ = 17228194480.

The previous prime is 21535243099. The next prime is 21535243109. The reversal of 21535243105 is 50134253512.

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 13991104656 + 7544138449 = 118284^2 + 86857^2 .

It is not a de Polignac number, because 21535243105 - 2³ = 21535243097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21535243109) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 2153524306 + ... + 2153524315.

It is an arithmetic number, because the mean of its divisors is an integer number (6460572933).

Almost surely, 2^21535243105 is an apocalyptic number.

It is an amenable number.

21535243105 is a deficient number, since it is larger than the sum of its proper divisors (4307048627).

21535243105 is an equidigital number, since it uses as much as digits as its factorization.

21535243105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4307048626.

The product of its (nonzero) digits is 18000, while the sum is 31.

Adding to 21535243105 its reverse (50134253512), we get a palindrome (71669496617).

The spelling of 21535243105 in words is "twenty-one billion, five hundred thirty-five million, two hundred forty-three thousand, one hundred five".