21000100111 has 2 divisors, whose sum is σ = 21000100112. Its totient is φ = 21000100110.

The previous prime is 21000100097. The next prime is 21000100129. The reversal of 21000100111 is 11100100012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21000100111 - 2¹³ = 21000091919 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21000100094 and 21000100103.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000100181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500050055 + 10500050056.

It is an arithmetic number, because the mean of its divisors is an integer number (10500050056).

Almost surely, 2^21000100111 is an apocalyptic number.

21000100111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000100111 is an equidigital number, since it uses as much as digits as its factorization.

21000100111 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2, while the sum is 7.

Adding to 21000100111 its reverse (11100100012), we get a palindrome (32100200123).

Subtracting from 21000100111 its reverse (11100100012), we obtain a palindrome (9900000099).

The spelling of 21000100111 in words is "twenty-one billion, one hundred thousand, one hundred eleven".