21123131230221 has 8 divisors (see below), whose sum is σ = 29646499972320. Its totient is φ = 13340924987472.

The previous prime is 21123131230219. The next prime is 21123131230237. The reversal of 21123131230221 is 12203213132112.

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

It is not a de Polignac number, because 21123131230221 - 2¹ = 21123131230219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21123131230191 and 21123131230200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123131230211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 185290624770 + ... + 185290624883.

It is an arithmetic number, because the mean of its divisors is an integer number (3705812496540).

Almost surely, 2^{21123131230221} is an apocalyptic number.

It is an amenable number.

21123131230221 is a deficient number, since it is larger than the sum of its proper divisors (8523368742099).

21123131230221 is a wasteful number, since it uses less digits than its factorization.

21123131230221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 370581249675.

The product of its (nonzero) digits is 864, while the sum is 24.

Adding to 21123131230221 its reverse (12203213132112), we get a palindrome (33326344362333).

The spelling of 21123131230221 in words is "twenty-one trillion, one hundred twenty-three billion, one hundred thirty-one million, two hundred thirty thousand, two hundred twenty-one".