1221133213 has 4 divisors (see below), whose sum is σ = 1232336380. Its totient is φ = 1209930048.

The previous prime is 1221133159. The next prime is 1221133231. The reversal of 1221133213 is 3123311221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3123311221 = 251 ⋅12443471.

It can be written as a sum of positive squares in 2 ways, for example, as 363931929 + 857201284 = 19077^2 + 29278^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221133213 - 2⁹ = 1221132701 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221133313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5601420 + ... + 5601637.

It is an arithmetic number, because the mean of its divisors is an integer number (308084095).

Almost surely, 2^1221133213 is an apocalyptic number.

It is an amenable number.

1221133213 is a deficient number, since it is larger than the sum of its proper divisors (11203167).

1221133213 is a wasteful number, since it uses less digits than its factorization.

1221133213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11203166.

The product of its digits is 216, while the sum is 19.

The square root of 1221133213 is about 34944.7165248196. The cubic root of 1221133213 is about 1068.8604670514.

Adding to 1221133213 its reverse (3123311221), we get a palindrome (4344444434).

The spelling of 1221133213 in words is "one billion, two hundred twenty-one million, one hundred thirty-three thousand, two hundred thirteen".