1211100212121 has 4 divisors (see below), whose sum is σ = 1614800282832. Its totient is φ = 807400141412.

The previous prime is 1211100212111. The next prime is 1211100212237. The reversal of 1211100212121 is 1212120011121.

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 1211100212121 - 2⁹ = 1211100211609 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1211100212121.

It is not an unprimeable number, because it can be changed into a prime (1211100212111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 201850035351 + ... + 201850035356.

It is an arithmetic number, because the mean of its divisors is an integer number (403700070708).

Almost surely, 2^{1211100212121} is an apocalyptic number.

It is an amenable number.

1211100212121 is a deficient number, since it is larger than the sum of its proper divisors (403700070711).

1211100212121 is an equidigital number, since it uses as much as digits as its factorization.

1211100212121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 403700070710.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1211100212121 its reverse (1212120011121), we get a palindrome (2423220223242).

The spelling of 1211100212121 in words is "one trillion, two hundred eleven billion, one hundred million, two hundred twelve thousand, one hundred twenty-one".