21210231121 has 2 divisors, whose sum is σ = 21210231122. Its totient is φ = 21210231120.

The previous prime is 21210231089. The next prime is 21210231187. The reversal of 21210231121 is 12113201212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19743341121 + 1466890000 = 140511^2 + 38300^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210231121 - 2⁵ = 21210231089 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21210231095 and 21210231104.

It is not a weakly prime, because it can be changed into another prime (21210231191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605115560 + 10605115561.

It is an arithmetic number, because the mean of its divisors is an integer number (10605115561).

Almost surely, 2^21210231121 is an apocalyptic number.

It is an amenable number.

21210231121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210231121 is an equidigital number, since it uses as much as digits as its factorization.

21210231121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21210231121 its reverse (12113201212), we get a palindrome (33323432333).

The spelling of 21210231121 in words is "twenty-one billion, two hundred ten million, two hundred thirty-one thousand, one hundred twenty-one".