1221212133 has 20 divisors (see below), whose sum is σ = 1825686720. Its totient is φ = 813513672.

The previous prime is 1221212089. The next prime is 1221212143. The reversal of 1221212133 is 3312121221.

1221212133 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1221212133 - 2¹⁴ = 1221195749 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221212143) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 115378 + ... + 125516.

It is an arithmetic number, because the mean of its divisors is an integer number (91284336).

Almost surely, 2^1221212133 is an apocalyptic number.

It is an amenable number.

1221212133 is a deficient number, since it is larger than the sum of its proper divisors (604474587).

1221212133 is a wasteful number, since it uses less digits than its factorization.

1221212133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11638 (or 11629 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 1221212133 is about 34945.8457187689. The cubic root of 1221212133 is about 1068.8834928359.

Adding to 1221212133 its reverse (3312121221), we get a palindrome (4533333354).

The spelling of 1221212133 in words is "one billion, two hundred twenty-one million, two hundred twelve thousand, one hundred thirty-three".