1281745 has 4 divisors (see below), whose sum is σ = 1538100. Its totient is φ = 1025392.

The previous prime is 1281739. The next prime is 1281751. The reversal of 1281745 is 5471821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5471821 = 433 ⋅12637.

It is an interprime number because it is at equal distance from previous prime (1281739) and next prime (1281751).

It can be written as a sum of positive squares in 2 ways, for example, as 654481 + 627264 = 809^2 + 792^2 .

It is a cyclic number.

It is not a de Polignac number, because 1281745 - 2¹⁵ = 1248977 is a prime.

1281745 is a lucky number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 128170 + ... + 128179.

It is an arithmetic number, because the mean of its divisors is an integer number (384525).

2^1281745 is an apocalyptic number.

It is an amenable number.

1281745 is a deficient number, since it is larger than the sum of its proper divisors (256355).

1281745 is an equidigital number, since it uses as much as digits as its factorization.

1281745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256354.

The product of its digits is 2240, while the sum is 28.

The square root of 1281745 is about 1132.1417755741. The cubic root of 1281745 is about 108.6260224545.

The spelling of 1281745 in words is "one million, two hundred eighty-one thousand, seven hundred forty-five".