21351312135 has 48 divisors (see below), whose sum is σ = 37322348544. Its totient is φ = 11291265216.

The previous prime is 21351312127. The next prime is 21351312161. The reversal of 21351312135 is 53121315312.

21351312135 is a `hidden beast` number, since 2 + 1 + 3 + 513 + 12 + 135 = 666.

It is not a de Polignac number, because 21351312135 - 2³ = 21351312127 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21351312099 and 21351312108.

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 3392962 + ... + 3399248.

It is an arithmetic number, because the mean of its divisors is an integer number (777548928).

Almost surely, 2^21351312135 is an apocalyptic number.

21351312135 is a deficient number, since it is larger than the sum of its proper divisors (15971036409).

21351312135 is a wasteful number, since it uses less digits than its factorization.

21351312135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6924 (or 6921 counting only the distinct ones).

The product of its digits is 2700, while the sum is 27.

Adding to 21351312135 its reverse (53121315312), we get a palindrome (74472627447).

The spelling of 21351312135 in words is "twenty-one billion, three hundred fifty-one million, three hundred twelve thousand, one hundred thirty-five".