1212121213 has 4 divisors (see below), whose sum is σ = 1219127868. Its totient is φ = 1205114560.

The previous prime is 1212121181. The next prime is 1212121217. The reversal of 1212121213 is 3121212121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3121212121 = 17 ⋅183600713.

It can be written as a sum of positive squares in 2 ways, for example, as 940464889 + 271656324 = 30667^2 + 16482^2 .

It is a cyclic number.

It is not a de Polignac number, because 1212121213 - 2⁵ = 1212121181 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 (1212121217) 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, 3503068 + ... + 3503413.

It is an arithmetic number, because the mean of its divisors is an integer number (304781967).

Almost surely, 2^1212121213 is an apocalyptic number.

It is an amenable number.

1212121213 is a deficient number, since it is larger than the sum of its proper divisors (7006655).

1212121213 is an equidigital number, since it uses as much as digits as its factorization.

1212121213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7006654.

The product of its digits is 48, while the sum is 16.

The square root of 1212121213 is about 34815.5312037602. The cubic root of 1212121213 is about 1066.2245645191.

Adding to 1212121213 its reverse (3121212121), we get a palindrome (4333333334).

It can be divided in two parts, 121212121 and 3, that multiplied together give a palindrome (363636363).

The spelling of 1212121213 in words is "one billion, two hundred twelve million, one hundred twenty-one thousand, two hundred thirteen".