21636044799 has 32 divisors (see below), whose sum is σ = 30535569408. Its totient is φ = 13608000000.

The previous prime is 21636044791. The next prime is 21636044821. The reversal of 21636044799 is 99744063612.

It is a happy number.

It is not a de Polignac number, because 21636044799 - 2³ = 21636044791 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21636044791) 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 31 ways as a sum of consecutive naturals, for example, 624174 + ... + 657924.

It is an arithmetic number, because the mean of its divisors is an integer number (954236544).

Almost surely, 2^21636044799 is an apocalyptic number.

21636044799 is a deficient number, since it is larger than the sum of its proper divisors (8899524609).

21636044799 is a wasteful number, since it uses less digits than its factorization.

21636044799 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33959.

The product of its (nonzero) digits is 1959552, while the sum is 51.

It can be divided in two parts, 2163604 and 4799, that added together give a triangular number (2168403 = T₂₀₈₂).

The spelling of 21636044799 in words is "twenty-one billion, six hundred thirty-six million, forty-four thousand, seven hundred ninety-nine".