21603635603 has 24 divisors (see below), whose sum is σ = 23878343328. Its totient is φ = 19530720000.

The previous prime is 21603635567. The next prime is 21603635657. The reversal of 21603635603 is 30653630612.

It is not a de Polignac number, because 21603635603 - 2¹⁰ = 21603634579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21603635693) 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 23 ways as a sum of consecutive naturals, for example, 26249450 + ... + 26250272.

It is an arithmetic number, because the mean of its divisors is an integer number (994930972).

Almost surely, 2^21603635603 is an apocalyptic number.

21603635603 is a deficient number, since it is larger than the sum of its proper divisors (2274707725).

21603635603 is a wasteful number, since it uses less digits than its factorization.

21603635603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1787 (or 1776 counting only the distinct ones).

The product of its (nonzero) digits is 58320, while the sum is 35.

The spelling of 21603635603 in words is "twenty-one billion, six hundred three million, six hundred thirty-five thousand, six hundred three".