1211212511 has 2 divisors, whose sum is σ = 1211212512. Its totient is φ = 1211212510.

The previous prime is 1211212489. The next prime is 1211212531. The reversal of 1211212511 is 1152121121.

It is a strong prime.

It is an emirp because it is prime and its reverse (1152121121) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211212511 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1211212511.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211212531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605606255 + 605606256.

It is an arithmetic number, because the mean of its divisors is an integer number (605606256).

Almost surely, 2^1211212511 is an apocalyptic number.

1211212511 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211212511 is an equidigital number, since it uses as much as digits as its factorization.

1211212511 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40, while the sum is 17.

The square root of 1211212511 is about 34802.4785180596. The cubic root of 1211212511 is about 1065.9580558011.

Adding to 1211212511 its reverse (1152121121), we get a palindrome (2363333632).

The spelling of 1211212511 in words is "one billion, two hundred eleven million, two hundred twelve thousand, five hundred eleven".