21232123221 has 16 divisors (see below), whose sum is σ = 28408797248. Its totient is φ = 14105145600.

The previous prime is 21232123217. The next prime is 21232123223. The reversal of 21232123221 is 12232123212.

It is not a de Polignac number, because 21232123221 - 2² = 21232123217 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 (21232123223) 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, 2362266 + ... + 2371236.

It is an arithmetic number, because the mean of its divisors is an integer number (1775549828).

Almost surely, 2^21232123221 is an apocalyptic number.

It is an amenable number.

21232123221 is a deficient number, since it is larger than the sum of its proper divisors (7176674027).

21232123221 is a wasteful number, since it uses less digits than its factorization.

21232123221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11652.

The product of its digits is 576, while the sum is 21.

Adding to 21232123221 its reverse (12232123212), we get a palindrome (33464246433).

Subtracting from 21232123221 its reverse (12232123212), we obtain a palindrome (9000000009).

It can be divided in two parts, 21232 and 123221, that added together give a triangular number (144453 = T₅₃₇).

The spelling of 21232123221 in words is "twenty-one billion, two hundred thirty-two million, one hundred twenty-three thousand, two hundred twenty-one".