21331013221 has 16 divisors (see below), whose sum is σ = 24635121280. Its totient is φ = 18091563840.

The previous prime is 21331013213. The next prime is 21331013239. The reversal of 21331013221 is 12231013312.

It is not a de Polignac number, because 21331013221 - 2³ = 21331013213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331013321) 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, 559126 + ... + 596056.

It is an arithmetic number, because the mean of its divisors is an integer number (1539695080).

Almost surely, 2^21331013221 is an apocalyptic number.

It is an amenable number.

21331013221 is a deficient number, since it is larger than the sum of its proper divisors (3304108059).

21331013221 is a wasteful number, since it uses less digits than its factorization.

21331013221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37804.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21331013221 its reverse (12231013312), we get a palindrome (33562026533).

Subtracting from 21331013221 its reverse (12231013312), we obtain a palindrome (9099999909).

The spelling of 21331013221 in words is "twenty-one billion, three hundred thirty-one million, thirteen thousand, two hundred twenty-one".