11991306461 has 2 divisors, whose sum is σ = 11991306462. Its totient is φ = 11991306460.

The previous prime is 11991306451. The next prime is 11991306463. The reversal of 11991306461 is 16460319911.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6335364025 + 5655942436 = 79595^2 + 75206^2 .

It is a cyclic number.

It is not a de Polignac number, because 11991306461 - 2¹⁰ = 11991305437 is a prime.

It is a super-3 number, since 3×11991306461³ (a number of 31 digits) contains 333 as substring.

Together with 11991306463, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11991306463) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5995653230 + 5995653231.

It is an arithmetic number, because the mean of its divisors is an integer number (5995653231).

Almost surely, 2^11991306461 is an apocalyptic number.

It is an amenable number.

11991306461 is a deficient number, since it is larger than the sum of its proper divisors (1).

11991306461 is an equidigital number, since it uses as much as digits as its factorization.

11991306461 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34992, while the sum is 41.

The spelling of 11991306461 in words is "eleven billion, nine hundred ninety-one million, three hundred six thousand, four hundred sixty-one".