1211110221 has 4 divisors (see below), whose sum is σ = 1614813632. Its totient is φ = 807406812.

The previous prime is 1211110213. The next prime is 1211110231. The reversal of 1211110221 is 1220111121.

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 not a de Polignac number, because 1211110221 - 2³ = 1211110213 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1211110197 and 1211110206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211110231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 201851701 + ... + 201851706.

It is an arithmetic number, because the mean of its divisors is an integer number (403703408).

Almost surely, 2^1211110221 is an apocalyptic number.

It is an amenable number.

1211110221 is a deficient number, since it is larger than the sum of its proper divisors (403703411).

1211110221 is an equidigital number, since it uses as much as digits as its factorization.

1211110221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 403703410.

The product of its (nonzero) digits is 8, while the sum is 12.

The square root of 1211110221 is about 34801.0089077889. The cubic root of 1211110221 is about 1065.9280473266.

Adding to 1211110221 its reverse (1220111121), we get a palindrome (2431221342).

The spelling of 1211110221 in words is "one billion, two hundred eleven million, one hundred ten thousand, two hundred twenty-one".