211311231221 has 4 divisors (see below), whose sum is σ = 215807214912. Its totient is φ = 206815247532.

The previous prime is 211311231203. The next prime is 211311231227. The reversal of 211311231221 is 122132113112.

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 a de Polignac number, because none of the positive numbers 2^k-211311231221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 211311231193 and 211311231202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211311231227) 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, 2247991775 + ... + 2247991868.

It is an arithmetic number, because the mean of its divisors is an integer number (53951803728).

Almost surely, 2^211311231221 is an apocalyptic number.

It is an amenable number.

211311231221 is a deficient number, since it is larger than the sum of its proper divisors (4495983691).

211311231221 is an equidigital number, since it uses as much as digits as its factorization.

211311231221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4495983690.

The product of its digits is 144, while the sum is 20.

Adding to 211311231221 its reverse (122132113112), we get a palindrome (333443344333).

The spelling of 211311231221 in words is "two hundred eleven billion, three hundred eleven million, two hundred thirty-one thousand, two hundred twenty-one".