21000012211111 has 2 divisors, whose sum is σ = 21000012211112. Its totient is φ = 21000012211110.

The previous prime is 21000012211097. The next prime is 21000012211121. The reversal of 21000012211111 is 11111221000012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21000012211111 - 2²¹ = 21000010113959 is a prime.

It is a super-2 number, since 2×21000012211111² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21000012211091 and 21000012211100.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000012211121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500006105555 + 10500006105556.

It is an arithmetic number, because the mean of its divisors is an integer number (10500006105556).

Almost surely, 2^{21000012211111} is an apocalyptic number.

21000012211111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000012211111 is an equidigital number, since it uses as much as digits as its factorization.

21000012211111 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21000012211111 its reverse (11111221000012), we get a palindrome (32111233211123).

The spelling of 21000012211111 in words is "twenty-one trillion, twelve million, two hundred eleven thousand, one hundred eleven".