1281866 has 4 divisors (see below), whose sum is σ = 1922802. Its totient is φ = 640932.

The previous prime is 1281853. The next prime is 1281871. The reversal of 1281866 is 6681821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6681821 = 587 ⋅11383.

It can be written as a sum of positive squares in only one way, i.e., 1274641 + 7225 = 1129^2 + 85^2 .

It is a Curzon 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 as a sum of consecutive naturals, namely, 320465 + ... + 320468.

2^1281866 is an apocalyptic number.

1281866 is a deficient number, since it is larger than the sum of its proper divisors (640936).

1281866 is an equidigital number, since it uses as much as digits as its factorization.

1281866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 640935.

The product of its digits is 4608, while the sum is 32.

The square root of 1281866 is about 1132.1952128498. The cubic root of 1281866 is about 108.6294405382.

The spelling of 1281866 in words is "one million, two hundred eighty-one thousand, eight hundred sixty-six".