1211500813 has 2 divisors, whose sum is σ = 1211500814. Its totient is φ = 1211500812.

The previous prime is 1211500783. The next prime is 1211500847. The reversal of 1211500813 is 3180051121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1211248809 + 252004 = 34803^2 + 502^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211500813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211500853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605750406 + 605750407.

It is an arithmetic number, because the mean of its divisors is an integer number (605750407).

Almost surely, 2^1211500813 is an apocalyptic number.

It is an amenable number.

1211500813 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211500813 is an equidigital number, since it uses as much as digits as its factorization.

1211500813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 240, while the sum is 22.

The square root of 1211500813 is about 34806.6202467289. The cubic root of 1211500813 is about 1066.0426249020.

Adding to 1211500813 its reverse (3180051121), we get a palindrome (4391551934).

The spelling of 1211500813 in words is "one billion, two hundred eleven million, five hundred thousand, eight hundred thirteen".