1211212111121 has 4 divisors (see below), whose sum is σ = 1214871362544. Its totient is φ = 1207552859700.

The previous prime is 1211212111111. The next prime is 1211212111129. The reversal of 1211212111121 is 1211112121121.

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 1211212111121 - 2¹⁴ = 1211212094737 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1211212111121.

It is not an unprimeable number, because it can be changed into a prime (1211212111129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1829625215 + ... + 1829625876.

It is an arithmetic number, because the mean of its divisors is an integer number (303717840636).

Almost surely, 2^{1211212111121} is an apocalyptic number.

It is an amenable number.

1211212111121 is a deficient number, since it is larger than the sum of its proper divisors (3659251423).

1211212111121 is an equidigital number, since it uses as much as digits as its factorization.

1211212111121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3659251422.

The product of its digits is 16, while the sum is 17.

Adding to 1211212111121 its reverse (1211112121121), we get a palindrome (2422324232242).

The spelling of 1211212111121 in words is "one trillion, two hundred eleven billion, two hundred twelve million, one hundred eleven thousand, one hundred twenty-one".