21003111221 has 8 divisors (see below), whose sum is σ = 21498169440. Its totient is φ = 20508353712.

The previous prime is 21003111187. The next prime is 21003111223. The reversal of 21003111221 is 12211130012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21003111221 - 2¹⁰ = 21003110197 is a prime.

It is a super-2 number, since 2×21003111221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21003111196 and 21003111205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003111223) 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 7 ways as a sum of consecutive naturals, for example, 69395 + ... + 216383.

It is an arithmetic number, because the mean of its divisors is an integer number (2687271180).

Almost surely, 2^21003111221 is an apocalyptic number.

It is an amenable number.

21003111221 is a deficient number, since it is larger than the sum of its proper divisors (495058219).

21003111221 is a wasteful number, since it uses less digits than its factorization.

21003111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150355.

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

Adding to 21003111221 its reverse (12211130012), we get a palindrome (33214241233).

The spelling of 21003111221 in words is "twenty-one billion, three million, one hundred eleven thousand, two hundred twenty-one".