21013121131111 has 2 divisors, whose sum is σ = 21013121131112. Its totient is φ = 21013121131110.

The previous prime is 21013121131073. The next prime is 21013121131183. The reversal of 21013121131111 is 11113112131012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21013121131111 - 2¹⁹ = 21013120606823 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21013121131511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506560565555 + 10506560565556.

It is an arithmetic number, because the mean of its divisors is an integer number (10506560565556).

Almost surely, 2^{21013121131111} is an apocalyptic number.

21013121131111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21013121131111 is an equidigital number, since it uses as much as digits as its factorization.

21013121131111 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36, while the sum is 19.

Adding to 21013121131111 its reverse (11113112131012), we get a palindrome (32126233262123).

Subtracting from 21013121131111 its reverse (11113112131012), we obtain a palindrome (9900009000099).

The spelling of 21013121131111 in words is "twenty-one trillion, thirteen billion, one hundred twenty-one million, one hundred thirty-one thousand, one hundred eleven".