21135305255 has 8 divisors (see below), whose sum is σ = 25379408400. Its totient is φ = 16896882816.

The previous prime is 21135305251. The next prime is 21135305273. The reversal of 21135305255 is 55250353112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21135305255 - 2² = 21135305251 is a prime.

It is a super-2 number, since 2×21135305255² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21135305251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1411985 + ... + 1426874.

It is an arithmetic number, because the mean of its divisors is an integer number (3172426050).

Almost surely, 2^21135305255 is an apocalyptic number.

21135305255 is a deficient number, since it is larger than the sum of its proper divisors (4244103145).

21135305255 is a wasteful number, since it uses less digits than its factorization.

21135305255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2840353.

The product of its (nonzero) digits is 22500, while the sum is 32.

Adding to 21135305255 its reverse (55250353112), we get a palindrome (76385658367).

The spelling of 21135305255 in words is "twenty-one billion, one hundred thirty-five million, three hundred five thousand, two hundred fifty-five".