21203131113121 has 4 divisors (see below), whose sum is σ = 21887103084544. Its totient is φ = 20519159141700.

The previous prime is 21203131113107. The next prime is 21203131113137. The reversal of 21203131113121 is 12131113130212.

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.

It is a cyclic number.

It is not a de Polignac number, because 21203131113121 - 2⁷ = 21203131112993 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21203131113092 and 21203131113101.

It is not an unprimeable number, because it can be changed into a prime (21203131113421) 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, 341985985665 + ... + 341985985726.

It is an arithmetic number, because the mean of its divisors is an integer number (5471775771136).

Almost surely, 2^{21203131113121} is an apocalyptic number.

It is an amenable number.

21203131113121 is a deficient number, since it is larger than the sum of its proper divisors (683971971423).

21203131113121 is an equidigital number, since it uses as much as digits as its factorization.

21203131113121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 683971971422.

The product of its (nonzero) digits is 216, while the sum is 22.

Adding to 21203131113121 its reverse (12131113130212), we get a palindrome (33334244243333).

The spelling of 21203131113121 in words is "twenty-one trillion, two hundred three billion, one hundred thirty-one million, one hundred thirteen thousand, one hundred twenty-one".