21256323535 has 4 divisors (see below), whose sum is σ = 25507588248. Its totient is φ = 17005058824.

The previous prime is 21256323533. The next prime is 21256323593. The reversal of 21256323535 is 53532365212.

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 21256323535 - 2¹ = 21256323533 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21256323494 and 21256323503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21256323533) 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, 2125632349 + ... + 2125632358.

It is an arithmetic number, because the mean of its divisors is an integer number (6376897062).

Almost surely, 2^21256323535 is an apocalyptic number.

21256323535 is a deficient number, since it is larger than the sum of its proper divisors (4251264713).

21256323535 is an equidigital number, since it uses as much as digits as its factorization.

21256323535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4251264712.

The product of its digits is 162000, while the sum is 37.

Adding to 21256323535 its reverse (53532365212), we get a palindrome (74788688747).

The spelling of 21256323535 in words is "twenty-one billion, two hundred fifty-six million, three hundred twenty-three thousand, five hundred thirty-five".