21331231312123 has 2 divisors, whose sum is σ = 21331231312124. Its totient is φ = 21331231312122.

The previous prime is 21331231311989. The next prime is 21331231312159. The reversal of 21331231312123 is 32121313213312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21331231312123 - 2¹³ = 21331231303931 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21331231312091 and 21331231312100.

It is not a weakly prime, because it can be changed into another prime (21331231318123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665615656061 + 10665615656062.

It is an arithmetic number, because the mean of its divisors is an integer number (10665615656062).

Almost surely, 2^{21331231312123} is an apocalyptic number.

21331231312123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21331231312123 is an equidigital number, since it uses as much as digits as its factorization.

21331231312123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 28.

Adding to 21331231312123 its reverse (32121313213312), we get a palindrome (53452544525435).

The spelling of 21331231312123 in words is "twenty-one trillion, three hundred thirty-one billion, two hundred thirty-one million, three hundred twelve thousand, one hundred twenty-three".