11926813781 has 2 divisors, whose sum is σ = 11926813782. Its totient is φ = 11926813780.

The previous prime is 11926813751. The next prime is 11926813823. The reversal of 11926813781 is 18731862911.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11912631025 + 14182756 = 109145^2 + 3766^2 .

It is an emirp because it is prime and its reverse (18731862911) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11926813781 is a prime.

It is a super-2 number, since 2×11926813781² (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 (11926813721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5963406890 + 5963406891.

It is an arithmetic number, because the mean of its divisors is an integer number (5963406891).

Almost surely, 2^11926813781 is an apocalyptic number.

It is an amenable number.

11926813781 is a deficient number, since it is larger than the sum of its proper divisors (1).

11926813781 is an equidigital number, since it uses as much as digits as its factorization.

11926813781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 47.

The spelling of 11926813781 in words is "eleven billion, nine hundred twenty-six million, eight hundred thirteen thousand, seven hundred eighty-one".