12777315781 has 2 divisors, whose sum is σ = 12777315782. Its totient is φ = 12777315780.

The previous prime is 12777315769. The next prime is 12777315827. The reversal of 12777315781 is 18751377721.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8282820100 + 4494495681 = 91010^2 + 67041^2 .

It is an emirp because it is prime and its reverse (18751377721) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12777315781 - 2¹³ = 12777307589 is a prime.

It is a super-2 number, since 2×12777315781² (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 (12777315721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6388657890 + 6388657891.

It is an arithmetic number, because the mean of its divisors is an integer number (6388657891).

Almost surely, 2^12777315781 is an apocalyptic number.

It is an amenable number.

12777315781 is a deficient number, since it is larger than the sum of its proper divisors (1).

12777315781 is an equidigital number, since it uses as much as digits as its factorization.

12777315781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576240, while the sum is 49.

The spelling of 12777315781 in words is "twelve billion, seven hundred seventy-seven million, three hundred fifteen thousand, seven hundred eighty-one".