1211321101 has 4 divisors (see below), whose sum is σ = 1211644252. Its totient is φ = 1210997952.

The previous prime is 1211321093. The next prime is 1211321123. The reversal of 1211321101 is 1011231121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1011231121 = 859 ⋅1177219.

It can be written as a sum of positive squares in 2 ways, for example, as 582063876 + 629257225 = 24126^2 + 25085^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211321101 - 2³ = 1211321093 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 (1211321701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155886 + ... + 163471.

It is an arithmetic number, because the mean of its divisors is an integer number (302911063).

Almost surely, 2^1211321101 is an apocalyptic number.

It is an amenable number.

1211321101 is a deficient number, since it is larger than the sum of its proper divisors (323151).

1211321101 is an equidigital number, since it uses as much as digits as its factorization.

1211321101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323150.

The product of its (nonzero) digits is 12, while the sum is 13.

The square root of 1211321101 is about 34804.0385731311. The cubic root of 1211321101 is about 1065.9899106367.

Adding to 1211321101 its reverse (1011231121), we get a palindrome (2222552222).

The spelling of 1211321101 in words is "one billion, two hundred eleven million, three hundred twenty-one thousand, one hundred one".