1211110121 has 4 divisors (see below), whose sum is σ = 1304272452. Its totient is φ = 1117947792.

The previous prime is 1211110091. The next prime is 1211110129. The reversal of 1211110121 is 1210111121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 261792400 + 949317721 = 16180^2 + 30811^2 .

It is not a de Polignac number, because 1211110121 - 2²² = 1206915817 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1211110129) 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, 46581146 + ... + 46581171.

It is an arithmetic number, because the mean of its divisors is an integer number (326068113).

Almost surely, 2^1211110121 is an apocalyptic number.

It is an amenable number.

1211110121 is a deficient number, since it is larger than the sum of its proper divisors (93162331).

1211110121 is an equidigital number, since it uses as much as digits as its factorization.

1211110121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93162330.

The product of its (nonzero) digits is 4, while the sum is 11.

The square root of 1211110121 is about 34801.0074710489. The cubic root of 1211110121 is about 1065.9280179891.

Adding to 1211110121 its reverse (1210111121), we get a palindrome (2421221242).

The spelling of 1211110121 in words is "one billion, two hundred eleven million, one hundred ten thousand, one hundred twenty-one".