21531122135 has 16 divisors (see below), whose sum is σ = 26982305280. Its totient is φ = 16462791840.

The previous prime is 21531122117. The next prime is 21531122143. The reversal of 21531122135 is 53122113512.

It is not a de Polignac number, because 21531122135 - 2¹⁰ = 21531121111 is a prime.

It is a congruent number.

It is an unprimeable number.

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, 70430 + ... + 219140.

It is an arithmetic number, because the mean of its divisors is an integer number (1686394080).

Almost surely, 2^21531122135 is an apocalyptic number.

21531122135 is a deficient number, since it is larger than the sum of its proper divisors (5451183145).

21531122135 is a wasteful number, since it uses less digits than its factorization.

21531122135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149998.

The product of its digits is 1800, while the sum is 26.

Adding to 21531122135 its reverse (53122113512), we get a palindrome (74653235647).

The spelling of 21531122135 in words is "twenty-one billion, five hundred thirty-one million, one hundred twenty-two thousand, one hundred thirty-five".