1213311121 has 4 divisors (see below), whose sum is σ = 1323612144. Its totient is φ = 1103010100.

The previous prime is 1213311103. The next prime is 1213311149. The reversal of 1213311121 is 1211133121.

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 1213311121 - 2¹⁷ = 1213180049 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1213311095 and 1213311104.

It is not an unprimeable number, because it can be changed into a prime (1213311161) 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, 55150495 + ... + 55150516.

It is an arithmetic number, because the mean of its divisors is an integer number (330903036).

Almost surely, 2^1213311121 is an apocalyptic number.

1213311121 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1213311121 is a deficient number, since it is larger than the sum of its proper divisors (110301023).

1213311121 is a wasteful number, since it uses less digits than its factorization.

1213311121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110301022.

The product of its digits is 36, while the sum is 16.

The square root of 1213311121 is about 34832.6157645388. The cubic root of 1213311121 is about 1066.5733454273.

Adding to 1213311121 its reverse (1211133121), we get a palindrome (2424444242).

The spelling of 1213311121 in words is "one billion, two hundred thirteen million, three hundred eleven thousand, one hundred twenty-one".