21101211211 has 4 divisors (see below), whose sum is σ = 21102339024. Its totient is φ = 21100083400.

The previous prime is 21101211193. The next prime is 21101211221. The reversal of 21101211211 is 11211210112.

It is a happy number.

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 21101211211 - 2⁵ = 21101211179 is a prime.

It is a super-2 number, since 2×21101211211² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21101211191 and 21101211200.

It is not an unprimeable number, because it can be changed into a prime (21101211221) 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, 535360 + ... + 573421.

It is an arithmetic number, because the mean of its divisors is an integer number (5275584756).

Almost surely, 2^21101211211 is an apocalyptic number.

21101211211 is a deficient number, since it is larger than the sum of its proper divisors (1127813).

21101211211 is a wasteful number, since it uses less digits than its factorization.

21101211211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1127812.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21101211211 its reverse (11211210112), we get a palindrome (32312421323).

The spelling of 21101211211 in words is "twenty-one billion, one hundred one million, two hundred eleven thousand, two hundred eleven".