21103021109 has 4 divisors (see below), whose sum is σ = 21103799616. Its totient is φ = 21102242604.

The previous prime is 21103021097. The next prime is 21103021193. The reversal of 21103021109 is 90112030112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21103021109 - 2³² = 16808053813 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 (21103021609) 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, 347069 + ... + 403314.

It is an arithmetic number, because the mean of its divisors is an integer number (5275949904).

Almost surely, 2^21103021109 is an apocalyptic number.

It is an amenable number.

21103021109 is a deficient number, since it is larger than the sum of its proper divisors (778507).

21103021109 is an equidigital number, since it uses as much as digits as its factorization.

21103021109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778506.

The product of its (nonzero) digits is 108, while the sum is 20.

The spelling of 21103021109 in words is "twenty-one billion, one hundred three million, twenty-one thousand, one hundred nine".