1278166 has 4 divisors (see below), whose sum is σ = 1917252. Its totient is φ = 639082.

The previous prime is 1278163. The next prime is 1278181. The reversal of 1278166 is 6618721.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6618721 = 2333 ⋅2837.

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 congruent number.

It is not an unprimeable number, because it can be changed into a prime (1278163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319540 + ... + 319543.

It is an arithmetic number, because the mean of its divisors is an integer number (479313).

2^1278166 is an apocalyptic number.

1278166 is a deficient number, since it is larger than the sum of its proper divisors (639086).

1278166 is an equidigital number, since it uses as much as digits as its factorization.

1278166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639085.

The product of its digits is 4032, while the sum is 31.

The square root of 1278166 is about 1130.5600382112. The cubic root of 1278166 is about 108.5248231905.

It can be divided in two parts, 1278 and 166, that added together give a square (1444 = 38²).

The spelling of 1278166 in words is "one million, two hundred seventy-eight thousand, one hundred sixty-six".