21355100111 has 2 divisors, whose sum is σ = 21355100112. Its totient is φ = 21355100110.

The previous prime is 21355100093. The next prime is 21355100159. The reversal of 21355100111 is 11100155312.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21355100111 - 2²⁶ = 21287991247 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21355100161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10677550055 + 10677550056.

It is an arithmetic number, because the mean of its divisors is an integer number (10677550056).

Almost surely, 2^21355100111 is an apocalyptic number.

21355100111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21355100111 is an equidigital number, since it uses as much as digits as its factorization.

21355100111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 150, while the sum is 20.

Adding to 21355100111 its reverse (11100155312), we get a palindrome (32455255423).

The spelling of 21355100111 in words is "twenty-one billion, three hundred fifty-five million, one hundred thousand, one hundred eleven".