1231212221121 has 4 divisors (see below), whose sum is σ = 1641616294832. Its totient is φ = 820808147412.

The previous prime is 1231212221089. The next prime is 1231212221171. The reversal of 1231212221121 is 1211222121321.

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 1231212221121 - 2⁵ = 1231212221089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1231212221171) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 205202036851 + ... + 205202036856.

It is an arithmetic number, because the mean of its divisors is an integer number (410404073708).

Almost surely, 2^{1231212221121} is an apocalyptic number.

It is an amenable number.

1231212221121 is a deficient number, since it is larger than the sum of its proper divisors (410404073711).

1231212221121 is an equidigital number, since it uses as much as digits as its factorization.

1231212221121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410404073710.

The product of its digits is 192, while the sum is 21.

Adding to 1231212221121 its reverse (1211222121321), we get a palindrome (2442434342442).

The spelling of 1231212221121 in words is "one trillion, two hundred thirty-one billion, two hundred twelve million, two hundred twenty-one thousand, one hundred twenty-one".