12801781 has 2 divisors, whose sum is σ = 12801782. Its totient is φ = 12801780.

The previous prime is 12801773. The next prime is 12801793. The reversal of 12801781 is 18710821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12215025 + 586756 = 3495^2 + 766^2 .

It is an emirp because it is prime and its reverse (18710821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12801781 - 2³ = 12801773 is a prime.

It is a super-2 number, since 2×12801781² = 327771193543922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12801751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6400890 + 6400891.

It is an arithmetic number, because the mean of its divisors is an integer number (6400891).

Almost surely, 2^12801781 is an apocalyptic number.

It is an amenable number.

12801781 is a deficient number, since it is larger than the sum of its proper divisors (1).

12801781 is an equidigital number, since it uses as much as digits as its factorization.

12801781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 896, while the sum is 28.

The square root of 12801781 is about 3577.9576576589. The cubic root of 12801781 is about 233.9322678780.

The spelling of 12801781 in words is "twelve million, eight hundred one thousand, seven hundred eighty-one".