21405521135 has 16 divisors (see below), whose sum is σ = 26014334976. Its totient is φ = 16906233888.

The previous prime is 21405521107. The next prime is 21405521171. The reversal of 21405521135 is 53112550412.

It is a cyclic number.

It is not a de Polignac number, because 21405521135 - 2¹⁰ = 21405520111 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21405521098 and 21405521107.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 599762 + ... + 634448.

It is an arithmetic number, because the mean of its divisors is an integer number (1625895936).

Almost surely, 2^21405521135 is an apocalyptic number.

21405521135 is a deficient number, since it is larger than the sum of its proper divisors (4608813841).

21405521135 is a wasteful number, since it uses less digits than its factorization.

21405521135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36262.

The product of its (nonzero) digits is 6000, while the sum is 29.

The spelling of 21405521135 in words is "twenty-one billion, four hundred five million, five hundred twenty-one thousand, one hundred thirty-five".