1213121113 has 2 divisors, whose sum is σ = 1213121114. Its totient is φ = 1213121112.

The previous prime is 1213121099. The next prime is 1213121137. The reversal of 1213121113 is 3111213121.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1122719049 + 90402064 = 33507^2 + 9508^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1213121113 is a prime.

It is not a weakly prime, because it can be changed into another prime (1213128113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606560556 + 606560557.

It is an arithmetic number, because the mean of its divisors is an integer number (606560557).

Almost surely, 2^1213121113 is an apocalyptic number.

It is an amenable number.

1213121113 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213121113 is an equidigital number, since it uses as much as digits as its factorization.

1213121113 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36, while the sum is 16.

The square root of 1213121113 is about 34829.8882140038. Note that the first 3 decimals coincide. The cubic root of 1213121113 is about 1066.5176663728.

Adding to 1213121113 its reverse (3111213121), we get a palindrome (4324334234).

The spelling of 1213121113 in words is "one billion, two hundred thirteen million, one hundred twenty-one thousand, one hundred thirteen".