21211111111187 has 2 divisors, whose sum is σ = 21211111111188. Its totient is φ = 21211111111186.

The previous prime is 21211111111181. The next prime is 21211111111199. The reversal of 21211111111187 is 78111111111212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21211111111187 - 2⁴² = 16813064600083 is a prime.

It is a super-2 number, since 2×21211111111187² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21211111111181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605555555593 + 10605555555594.

It is an arithmetic number, because the mean of its divisors is an integer number (10605555555594).

Almost surely, 2^{21211111111187} is an apocalyptic number.

21211111111187 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211111111187 is an equidigital number, since it uses as much as digits as its factorization.

21211111111187 is an evil number, because the sum of its binary digits is even.

The product of its digits is 224, while the sum is 29.

Adding to 21211111111187 its reverse (78111111111212), we get a palindrome (99322222222399).

The spelling of 21211111111187 in words is "twenty-one trillion, two hundred eleven billion, one hundred eleven million, one hundred eleven thousand, one hundred eighty-seven".