12105994781 has 2 divisors, whose sum is σ = 12105994782. Its totient is φ = 12105994780.

The previous prime is 12105994759. The next prime is 12105994787. The reversal of 12105994781 is 18749950121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7869286681 + 4236708100 = 88709^2 + 65090^2 .

It is a cyclic number.

It is not a de Polignac number, because 12105994781 - 2⁶ = 12105994717 is a prime.

It is a super-2 number, since 2×12105994781² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12105994787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6052997390 + 6052997391.

It is an arithmetic number, because the mean of its divisors is an integer number (6052997391).

Almost surely, 2^12105994781 is an apocalyptic number.

It is an amenable number.

12105994781 is a deficient number, since it is larger than the sum of its proper divisors (1).

12105994781 is an equidigital number, since it uses as much as digits as its factorization.

12105994781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 47.

The spelling of 12105994781 in words is "twelve billion, one hundred five million, nine hundred ninety-four thousand, seven hundred eighty-one".