21204402103 has 4 divisors (see below), whose sum is σ = 21204962608. Its totient is φ = 21203841600.

The previous prime is 21204402083. The next prime is 21204402143. The reversal of 21204402103 is 30120440212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21204402103 - 2³³ = 12614467511 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21204402143) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 219051 + ... + 300652.

It is an arithmetic number, because the mean of its divisors is an integer number (5301240652).

Almost surely, 2^21204402103 is an apocalyptic number.

21204402103 is a deficient number, since it is larger than the sum of its proper divisors (560505).

21204402103 is an equidigital number, since it uses as much as digits as its factorization.

21204402103 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 560504.

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 21204402103 its reverse (30120440212), we get a palindrome (51324842315).

The spelling of 21204402103 in words is "twenty-one billion, two hundred four million, four hundred two thousand, one hundred three".