21101100211 has 4 divisors (see below), whose sum is σ = 21118354992. Its totient is φ = 21083845432.

The previous prime is 21101100193. The next prime is 21101100227. The reversal of 21101100211 is 11200110112.

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

It is a cyclic number.

It is not a de Polignac number, because 21101100211 - 2⁹ = 21101099699 is a prime.

It is a super-2 number, since 2×21101100211² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21101100271) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8625556 + ... + 8628001.

It is an arithmetic number, because the mean of its divisors is an integer number (5279588748).

Almost surely, 2^21101100211 is an apocalyptic number.

21101100211 is a deficient number, since it is larger than the sum of its proper divisors (17254781).

21101100211 is a wasteful number, since it uses less digits than its factorization.

21101100211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17254780.

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21101100211 its reverse (11200110112), we get a palindrome (32301210323).

Subtracting from 21101100211 its reverse (11200110112), we obtain a palindrome (9900990099).

The spelling of 21101100211 in words is "twenty-one billion, one hundred one million, one hundred thousand, two hundred eleven".