1211530511 has 2 divisors, whose sum is σ = 1211530512. Its totient is φ = 1211530510.

The previous prime is 1211530427. The next prime is 1211530549. The reversal of 1211530511 is 1150351121.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1211530511 - 2¹⁴ = 1211514127 is a prime.

It is a super-2 number, since 2×1211530511² = 2935612358167842242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211430511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605765255 + 605765256.

It is an arithmetic number, because the mean of its divisors is an integer number (605765256).

Almost surely, 2^1211530511 is an apocalyptic number.

1211530511 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211530511 is an equidigital number, since it uses as much as digits as its factorization.

1211530511 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 150, while the sum is 20.

The square root of 1211530511 is about 34807.0468583590. The cubic root of 1211530511 is about 1066.0513356061.

Adding to 1211530511 its reverse (1150351121), we get a palindrome (2361881632).

The spelling of 1211530511 in words is "one billion, two hundred eleven million, five hundred thirty thousand, five hundred eleven".