21211010111 has 4 divisors (see below), whose sum is σ = 21416942352. Its totient is φ = 21005077872.

The previous prime is 21211010099. The next prime is 21211010129. The reversal of 21211010111 is 11101011212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21211010111 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211010092 and 21211010101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211010131) 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 in 3 ways as a sum of consecutive naturals, for example, 102965966 + ... + 102966171.

It is an arithmetic number, because the mean of its divisors is an integer number (5354235588).

Almost surely, 2^21211010111 is an apocalyptic number.

21211010111 is a deficient number, since it is larger than the sum of its proper divisors (205932241).

21211010111 is a wasteful number, since it uses less digits than its factorization.

21211010111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205932240.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21211010111 its reverse (11101011212), we get a palindrome (32312021323).

The spelling of 21211010111 in words is "twenty-one billion, two hundred eleven million, ten thousand, one hundred eleven".