21133541565 has 48 divisors (see below), whose sum is σ = 37384903296. Its totient is φ = 11041430400.

The previous prime is 21133541549. The next prime is 21133541593. The reversal of 21133541565 is 56514533112.

21133541565 is a `hidden beast` number, since 2 + 11 + 33 + 54 + 1 + 565 = 666.

It is not a de Polignac number, because 21133541565 - 2⁴ = 21133541549 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 (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 480550 + ... + 522680.

It is an arithmetic number, because the mean of its divisors is an integer number (778852152).

Almost surely, 2^21133541565 is an apocalyptic number.

It is an amenable number.

21133541565 is a deficient number, since it is larger than the sum of its proper divisors (16251361731).

21133541565 is a wasteful number, since it uses less digits than its factorization.

21133541565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42370 (or 42367 counting only the distinct ones).

The product of its digits is 54000, while the sum is 36.

The spelling of 21133541565 in words is "twenty-one billion, one hundred thirty-three million, five hundred forty-one thousand, five hundred sixty-five".