1281289 has 4 divisors (see below), whose sum is σ = 1285956. Its totient is φ = 1276624.

The previous prime is 1281283. The next prime is 1281317. The reversal of 1281289 is 9821821.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1016064 + 265225 = 1008^2 + 515^2 .

It is a cyclic number.

It is not a de Polignac number, because 1281289 - 2³ = 1281281 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1281289.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1281281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1894 + ... + 2479.

It is an arithmetic number, because the mean of its divisors is an integer number (321489).

2^1281289 is an apocalyptic number.

It is an amenable number.

1281289 is a deficient number, since it is larger than the sum of its proper divisors (4667).

1281289 is an equidigital number, since it uses as much as digits as its factorization.

1281289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4666.

The product of its digits is 2304, while the sum is 31.

The square root of 1281289 is about 1131.9403694542. The cubic root of 1281289 is about 108.6131391478.

The spelling of 1281289 in words is "one million, two hundred eighty-one thousand, two hundred eighty-nine".