1281429781 has 2 divisors, whose sum is σ = 1281429782. Its totient is φ = 1281429780.

The previous prime is 1281429763. The next prime is 1281429823. The reversal of 1281429781 is 1879241821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 950735556 + 330694225 = 30834^2 + 18185^2 .

It is an emirp because it is prime and its reverse (1879241821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1281429781 - 2²¹ = 1279332629 is a prime.

It is a super-2 number, since 2×1281429781² = 3284124567267415922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1281429701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 640714890 + 640714891.

It is an arithmetic number, because the mean of its divisors is an integer number (640714891).

Almost surely, 2^1281429781 is an apocalyptic number.

It is an amenable number.

1281429781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1281429781 is an equidigital number, since it uses as much as digits as its factorization.

1281429781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64512, while the sum is 43.

The square root of 1281429781 is about 35797.0638600430. The cubic root of 1281429781 is about 1086.1711694062.

The spelling of 1281429781 in words is "one billion, two hundred eighty-one million, four hundred twenty-nine thousand, seven hundred eighty-one".