21230013121 has 4 divisors (see below), whose sum is σ = 21230321200. Its totient is φ = 21229705044.

The previous prime is 21230013113. The next prime is 21230013131. The reversal of 21230013121 is 12131003212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21230013121 - 2³ = 21230013113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21230013095 and 21230013104.

It is not an unprimeable number, because it can be changed into a prime (21230013131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2050 + ... + 206068.

It is an arithmetic number, because the mean of its divisors is an integer number (5307580300).

Almost surely, 2^21230013121 is an apocalyptic number.

It is an amenable number.

21230013121 is a deficient number, since it is larger than the sum of its proper divisors (308079).

21230013121 is a wasteful number, since it uses less digits than its factorization.

21230013121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 308078.

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

Adding to 21230013121 its reverse (12131003212), we get a palindrome (33361016333).

Subtracting from 21230013121 its reverse (12131003212), we obtain a palindrome (9099009909).

The spelling of 21230013121 in words is "twenty-one billion, two hundred thirty million, thirteen thousand, one hundred twenty-one".