21103011221 has 4 divisors (see below), whose sum is σ = 22020533472. Its totient is φ = 20185488972.

The previous prime is 21103011203. The next prime is 21103011227. The reversal of 21103011221 is 12211030112.

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 21103011221 - 2¹⁴ = 21102994837 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21103011196 and 21103011205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21103011227) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 458761091 + ... + 458761136.

It is an arithmetic number, because the mean of its divisors is an integer number (5505133368).

Almost surely, 2^21103011221 is an apocalyptic number.

It is an amenable number.

21103011221 is a deficient number, since it is larger than the sum of its proper divisors (917522251).

21103011221 is an equidigital number, since it uses as much as digits as its factorization.

21103011221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 917522250.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21103011221 its reverse (12211030112), we get a palindrome (33314041333).

The spelling of 21103011221 in words is "twenty-one billion, one hundred three million, eleven thousand, two hundred twenty-one".