21211211101 has 4 divisors (see below), whose sum is σ = 21237366304. Its totient is φ = 21185055900.

The previous prime is 21211211071. The next prime is 21211211111. The reversal of 21211211101 is 10111211212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21211211101 - 2⁵ = 21211211069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211211111) 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, 13076385 + ... + 13078006.

It is an arithmetic number, because the mean of its divisors is an integer number (5309341576).

Almost surely, 2^21211211101 is an apocalyptic number.

It is an amenable number.

21211211101 is a deficient number, since it is larger than the sum of its proper divisors (26155203).

21211211101 is an equidigital number, since it uses as much as digits as its factorization.

21211211101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26155202.

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

Adding to 21211211101 its reverse (10111211212), we get a palindrome (31322422313).

The spelling of 21211211101 in words is "twenty-one billion, two hundred eleven million, two hundred eleven thousand, one hundred one".