21031012111 has 2 divisors, whose sum is σ = 21031012112. Its totient is φ = 21031012110.

The previous prime is 21031012099. The next prime is 21031012127. The reversal of 21031012111 is 11121013012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21031012111 - 2⁷ = 21031011983 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21031012091 and 21031012100.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21031012141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10515506055 + 10515506056.

It is an arithmetic number, because the mean of its divisors is an integer number (10515506056).

Almost surely, 2^21031012111 is an apocalyptic number.

21031012111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21031012111 is an equidigital number, since it uses as much as digits as its factorization.

21031012111 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12, while the sum is 13.

Adding to 21031012111 its reverse (11121013012), we get a palindrome (32152025123).

Subtracting from 21031012111 its reverse (11121013012), we obtain a palindrome (9909999099).

The spelling of 21031012111 in words is "twenty-one billion, thirty-one million, twelve thousand, one hundred eleven".