21636223815 has 32 divisors (see below), whose sum is σ = 34732293120. Its totient is φ = 11501271936.

The previous prime is 21636223813. The next prime is 21636223823. The reversal of 21636223815 is 51832263612.

It is a happy number.

It is not a de Polignac number, because 21636223815 - 2¹ = 21636223813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21636223811) 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 31 ways as a sum of consecutive naturals, for example, 10965169 + ... + 10967141.

It is an arithmetic number, because the mean of its divisors is an integer number (1085384160).

Almost surely, 2^21636223815 is an apocalyptic number.

21636223815 is a deficient number, since it is larger than the sum of its proper divisors (13096069305).

21636223815 is a wasteful number, since it uses less digits than its factorization.

21636223815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4023.

The product of its digits is 103680, while the sum is 39.

The spelling of 21636223815 in words is "twenty-one billion, six hundred thirty-six million, two hundred twenty-three thousand, eight hundred fifteen".