21556530763 has 16 divisors (see below), whose sum is σ = 22854656160. Its totient is φ = 20295878400.

The previous prime is 21556530761. The next prime is 21556530797. The reversal of 21556530763 is 36703565512.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21556530763 - 2¹ = 21556530761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21556530761) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 4243381 + ... + 4248457.

It is an arithmetic number, because the mean of its divisors is an integer number (1428416010).

Almost surely, 2^21556530763 is an apocalyptic number.

21556530763 is a deficient number, since it is larger than the sum of its proper divisors (1298125397).

21556530763 is a wasteful number, since it uses less digits than its factorization.

21556530763 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8718.

The product of its (nonzero) digits is 567000, while the sum is 43.

The spelling of 21556530763 in words is "twenty-one billion, five hundred fifty-six million, five hundred thirty thousand, seven hundred sixty-three".