21305147535 has 24 divisors (see below), whose sum is σ = 42204483360. Its totient is φ = 9739495872.

The previous prime is 21305147533. The next prime is 21305147543. The reversal of 21305147535 is 53574150312.

21305147535 is a `hidden beast` number, since 2 + 1 + 30 + 51 + 47 + 535 = 666.

It is not a de Polignac number, because 21305147535 - 2¹ = 21305147533 is a prime.

It is a super-2 number, since 2×21305147535² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21305147535.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21305147533) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 33817380 + ... + 33818009.

It is an arithmetic number, because the mean of its divisors is an integer number (1758520140).

Almost surely, 2^21305147535 is an apocalyptic number.

21305147535 is a deficient number, since it is larger than the sum of its proper divisors (20899335825).

21305147535 is a wasteful number, since it uses less digits than its factorization.

21305147535 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67635407 (or 67635404 counting only the distinct ones).

The product of its (nonzero) digits is 63000, while the sum is 36.

Adding to 21305147535 its reverse (53574150312), we get a palindrome (74879297847).

The spelling of 21305147535 in words is "twenty-one billion, three hundred five million, one hundred forty-seven thousand, five hundred thirty-five".