21100103221 has 4 divisors (see below), whose sum is σ = 21780751744. Its totient is φ = 20419454700.

The previous prime is 21100103207. The next prime is 21100103251. The reversal of 21100103221 is 12230100112.

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 a de Polignac number, because none of the positive numbers 2^k-21100103221 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 (21100103251) 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, 340324215 + ... + 340324276.

It is an arithmetic number, because the mean of its divisors is an integer number (5445187936).

Almost surely, 2^21100103221 is an apocalyptic number.

It is an amenable number.

21100103221 is a deficient number, since it is larger than the sum of its proper divisors (680648523).

21100103221 is an equidigital number, since it uses as much as digits as its factorization.

21100103221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 680648522.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21100103221 its reverse (12230100112), we get a palindrome (33330203333).

The spelling of 21100103221 in words is "twenty-one billion, one hundred million, one hundred three thousand, two hundred twenty-one".