21003311221 has 16 divisors (see below), whose sum is σ = 21414032640. Its totient is φ = 20596605120.

The previous prime is 21003311209. The next prime is 21003311233. The reversal of 21003311221 is 12211330012.

It is an interprime number because it is at equal distance from previous prime (21003311209) and next prime (21003311233).

It is a cyclic number.

It is not a de Polignac number, because 21003311221 - 2³³ = 12413376629 is a prime.

It is a super-2 number, since 2×21003311221² (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 = 21003311195 and 21003311204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003311201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16978615 + ... + 16979851.

It is an arithmetic number, because the mean of its divisors is an integer number (1338377040).

Almost surely, 2^21003311221 is an apocalyptic number.

It is an amenable number.

21003311221 is a deficient number, since it is larger than the sum of its proper divisors (410721419).

21003311221 is a wasteful number, since it uses less digits than its factorization.

21003311221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2604.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21003311221 its reverse (12211330012), we get a palindrome (33214641233).

The spelling of 21003311221 in words is "twenty-one billion, three million, three hundred eleven thousand, two hundred twenty-one".