1281811 has 4 divisors (see below), whose sum is σ = 1292032. Its totient is φ = 1271592.

The previous prime is 1281809. The next prime is 1281821. The reversal of 1281811 is 1181821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1181821 = 907 ⋅1303.

It is a cyclic number.

It is not a de Polignac number, because 1281811 - 2¹ = 1281809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1281821) 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 in 3 ways as a sum of consecutive naturals, for example, 4920 + ... + 5173.

It is an arithmetic number, because the mean of its divisors is an integer number (323008).

2^1281811 is an apocalyptic number.

1281811 is a deficient number, since it is larger than the sum of its proper divisors (10221).

1281811 is a wasteful number, since it uses less digits than its factorization.

1281811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10220.

The product of its digits is 128, while the sum is 22.

The square root of 1281811 is about 1132.1709234917. The cubic root of 1281811 is about 108.6278868904.

The spelling of 1281811 in words is "one million, two hundred eighty-one thousand, eight hundred eleven".