21103533636 has 24 divisors (see below), whose sum is σ = 50386732704. Its totient is φ = 6870917760.

The previous prime is 21103533599. The next prime is 21103533641. The reversal of 21103533636 is 63633530112.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21103533597 and 21103533606.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20448645 + ... + 20449676.

It is an arithmetic number, because the mean of its divisors is an integer number (2099447196).

Almost surely, 2^21103533636 is an apocalyptic number.

It is an amenable number.

21103533636 is an abundant number, since it is smaller than the sum of its proper divisors (29283199068).

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

21103533636 is a wasteful number, since it uses less digits than its factorization.

21103533636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40898371 (or 40898369 counting only the distinct ones).

The product of its (nonzero) digits is 29160, while the sum is 33.

The spelling of 21103533636 in words is "twenty-one billion, one hundred three million, five hundred thirty-three thousand, six hundred thirty-six".