21034211111 has 2 divisors, whose sum is σ = 21034211112. Its totient is φ = 21034211110.

The previous prime is 21034211087. The next prime is 21034211131. The reversal of 21034211111 is 11111243012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21034211111 - 2¹⁸ = 21033948967 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21034211111.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21034211131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10517105555 + 10517105556.

It is an arithmetic number, because the mean of its divisors is an integer number (10517105556).

Almost surely, 2^21034211111 is an apocalyptic number.

21034211111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21034211111 is an equidigital number, since it uses as much as digits as its factorization.

21034211111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 21034211111 its reverse (11111243012), we get a palindrome (32145454123).

The spelling of 21034211111 in words is "twenty-one billion, thirty-four million, two hundred eleven thousand, one hundred eleven".