1211213305 has 4 divisors (see below), whose sum is σ = 1453455972. Its totient is φ = 968970640.

The previous prime is 1211213287. The next prime is 1211213329. The reversal of 1211213305 is 5033121121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5033121121 = 7 ⋅719017303.

It can be written as a sum of positive squares in 2 ways, for example, as 530473024 + 680740281 = 23032^2 + 26091^2 .

It is not a de Polignac number, because 1211213305 - 2⁷ = 1211213177 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121121326 + ... + 121121335.

It is an arithmetic number, because the mean of its divisors is an integer number (363363993).

Almost surely, 2^1211213305 is an apocalyptic number.

It is an amenable number.

1211213305 is a deficient number, since it is larger than the sum of its proper divisors (242242667).

1211213305 is an equidigital number, since it uses as much as digits as its factorization.

1211213305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242242666.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 1211213305 is about 34802.4899252913. The cubic root of 1211213305 is about 1065.9582887276.

Adding to 1211213305 its reverse (5033121121), we get a palindrome (6244334426).

The spelling of 1211213305 in words is "one billion, two hundred eleven million, two hundred thirteen thousand, three hundred five".