21405310135 has 64 divisors (see below), whose sum is σ = 29217936384. Its totient is φ = 14919091200.

The previous prime is 21405310127. The next prime is 21405310139. The reversal of 21405310135 is 53101350412.

It is a happy number.

It is not a de Polignac number, because 21405310135 - 2³ = 21405310127 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21405310139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 36465312 + ... + 36465898.

It is an arithmetic number, because the mean of its divisors is an integer number (456530256).

Almost surely, 2^21405310135 is an apocalyptic number.

21405310135 is a deficient number, since it is larger than the sum of its proper divisors (7812626249).

21405310135 is a wasteful number, since it uses less digits than its factorization.

21405310135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 904.

The product of its (nonzero) digits is 1800, while the sum is 25.

Adding to 21405310135 its reverse (53101350412), we get a palindrome (74506660547).

The spelling of 21405310135 in words is "twenty-one billion, four hundred five million, three hundred ten thousand, one hundred thirty-five".