21535243111 has 4 divisors (see below), whose sum is σ = 21535740072. Its totient is φ = 21534746152.

The previous prime is 21535243109. The next prime is 21535243133. The reversal of 21535243111 is 11134253512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21535243111 - 2¹ = 21535243109 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21535243111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21535243151) by changing a digit.

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, 176536 + ... + 272461.

It is an arithmetic number, because the mean of its divisors is an integer number (5383935018).

Almost surely, 2^21535243111 is an apocalyptic number.

21535243111 is a deficient number, since it is larger than the sum of its proper divisors (496961).

21535243111 is an equidigital number, since it uses as much as digits as its factorization.

21535243111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 496960.

The product of its digits is 3600, while the sum is 28.

Adding to 21535243111 its reverse (11134253512), we get a palindrome (32669496623).

The spelling of 21535243111 in words is "twenty-one billion, five hundred thirty-five million, two hundred forty-three thousand, one hundred eleven".