1221233213 has 4 divisors (see below), whose sum is σ = 1224373020. Its totient is φ = 1218093408.

The previous prime is 1221233183. The next prime is 1221233219. The reversal of 1221233213 is 3123321221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 573937849 + 647295364 = 23957^2 + 25442^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221233213 - 2¹⁰ = 1221232189 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 (1221233219) 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, 1569320 + ... + 1570097.

It is an arithmetic number, because the mean of its divisors is an integer number (306093255).

Almost surely, 2^1221233213 is an apocalyptic number.

It is an amenable number.

1221233213 is a deficient number, since it is larger than the sum of its proper divisors (3139807).

1221233213 is an equidigital number, since it uses as much as digits as its factorization.

1221233213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3139806.

The product of its digits is 432, while the sum is 20.

The square root of 1221233213 is about 34946.1473269944. The cubic root of 1221233213 is about 1068.8896429917.

Adding to 1221233213 its reverse (3123321221), we get a palindrome (4344554434).

The spelling of 1221233213 in words is "one billion, two hundred twenty-one million, two hundred thirty-three thousand, two hundred thirteen".