21636396036 has 18 divisors (see below), whose sum is σ = 54692001182. Its totient is φ = 7212132000.

The previous prime is 21636396017. The next prime is 21636396071. The reversal of 21636396036 is 63069363612.

21636396036 is a `hidden beast` number, since 2 + 1 + 6 + 3 + 6 + 39 + 603 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21607236036 + 29160000 = 146994^2 + 5400^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a junction number, because it is equal to n+sod(n) for n = 21636395982 and 21636396000.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 300505465 + ... + 300505536.

Almost surely, 2^21636396036 is an apocalyptic number.

It is an amenable number.

21636396036 is an abundant number, since it is smaller than the sum of its proper divisors (33055605146).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21636396036 is a wasteful number, since it uses less digits than its factorization.

21636396036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 601011011 (or 601011006 counting only the distinct ones).

The product of its (nonzero) digits is 629856, while the sum is 45.

The spelling of 21636396036 in words is "twenty-one billion, six hundred thirty-six million, three hundred ninety-six thousand, thirty-six".