21535243033 has 4 divisors (see below), whose sum is σ = 21732814180. Its totient is φ = 21337671888.

The previous prime is 21535243007. The next prime is 21535243049. The reversal of 21535243033 is 33034253512.

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 8469152784 + 13066090249 = 92028^2 + 114307^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21535243033 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21535242986 and 21535243004.

It is not an unprimeable number, because it can be changed into a prime (21535243133) 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, 98785410 + ... + 98785627.

It is an arithmetic number, because the mean of its divisors is an integer number (5433203545).

Almost surely, 2^21535243033 is an apocalyptic number.

It is an amenable number.

21535243033 is a deficient number, since it is larger than the sum of its proper divisors (197571147).

21535243033 is a wasteful number, since it uses less digits than its factorization.

21535243033 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197571146.

The product of its (nonzero) digits is 32400, while the sum is 31.

Adding to 21535243033 its reverse (33034253512), we get a palindrome (54569496545).

The spelling of 21535243033 in words is "twenty-one billion, five hundred thirty-five million, two hundred forty-three thousand, thirty-three".