21204505135 has 32 divisors (see below), whose sum is σ = 28079654400. Its totient is φ = 15244118400.

The previous prime is 21204505109. The next prime is 21204505139. The reversal of 21204505135 is 53150540212.

It is not a de Polignac number, because 21204505135 - 2¹⁷ = 21204374063 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21204505139) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1723014 + ... + 1735276.

It is an arithmetic number, because the mean of its divisors is an integer number (877489200).

Almost surely, 2^21204505135 is an apocalyptic number.

21204505135 is a deficient number, since it is larger than the sum of its proper divisors (6875149265).

21204505135 is a wasteful number, since it uses less digits than its factorization.

21204505135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12639.

The product of its (nonzero) digits is 6000, while the sum is 28.

The spelling of 21204505135 in words is "twenty-one billion, two hundred four million, five hundred five thousand, one hundred thirty-five".