11812078781 has 2 divisors, whose sum is σ = 11812078782. Its totient is φ = 11812078780.

The previous prime is 11812078763. The next prime is 11812078787. The reversal of 11812078781 is 18787021811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11140802500 + 671276281 = 105550^2 + 25909^2 .

It is a cyclic number.

It is not a de Polignac number, because 11812078781 - 2³⁰ = 10738336957 is a prime.

It is a super-2 number, since 2×11812078781² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11812078787) 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, 5906039390 + 5906039391.

It is an arithmetic number, because the mean of its divisors is an integer number (5906039391).

Almost surely, 2^11812078781 is an apocalyptic number.

It is an amenable number.

11812078781 is a deficient number, since it is larger than the sum of its proper divisors (1).

11812078781 is an equidigital number, since it uses as much as digits as its factorization.

11812078781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 50176, while the sum is 44.

The spelling of 11812078781 in words is "eleven billion, eight hundred twelve million, seventy-eight thousand, seven hundred eighty-one".