21513135405 has 32 divisors (see below), whose sum is σ = 34908587136. Its totient is φ = 11311294464.

The previous prime is 21513135383. The next prime is 21513135419. The reversal of 21513135405 is 50453131512.

It is not a de Polignac number, because 21513135405 - 2⁵ = 21513135373 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 (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3986389 + ... + 3991781.

It is an arithmetic number, because the mean of its divisors is an integer number (1090893348).

Almost surely, 2^21513135405 is an apocalyptic number.

It is an amenable number.

21513135405 is a deficient number, since it is larger than the sum of its proper divisors (13395451731).

21513135405 is a wasteful number, since it uses less digits than its factorization.

21513135405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9117.

The product of its (nonzero) digits is 9000, while the sum is 30.

Adding to 21513135405 its reverse (50453131512), we get a palindrome (71966266917).

The spelling of 21513135405 in words is "twenty-one billion, five hundred thirteen million, one hundred thirty-five thousand, four hundred five".