21253332535 has 16 divisors (see below), whose sum is σ = 25797719232. Its totient is φ = 16807392000.

The previous prime is 21253332533. The next prime is 21253332539. The reversal of 21253332535 is 53523335212.

It is not a de Polignac number, because 21253332535 - 2¹ = 21253332533 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 21253332535.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253332533) 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 15 ways as a sum of consecutive naturals, for example, 285307 + ... + 352003.

It is an arithmetic number, because the mean of its divisors is an integer number (1612357452).

Almost surely, 2^21253332535 is an apocalyptic number.

21253332535 is a deficient number, since it is larger than the sum of its proper divisors (4544386697).

21253332535 is a wasteful number, since it uses less digits than its factorization.

21253332535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67434.

The product of its digits is 81000, while the sum is 34.

Adding to 21253332535 its reverse (53523335212), we get a palindrome (74776667747).

The spelling of 21253332535 in words is "twenty-one billion, two hundred fifty-three million, three hundred thirty-two thousand, five hundred thirty-five".