1278666 has 28 divisors (see below), whose sum is σ = 2878962. Its totient is φ = 425736.

The previous prime is 1278659. The next prime is 1278671. The reversal of 1278666 is 6668721.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 893025 + 385641 = 945^2 + 621^2 .

It is a super-3 number, since 3×1278666³ = 6271805862963336888, which contains 333 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1278666.

It is an unprimeable number.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 1020 + ... + 1896.

2^1278666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1278666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1439481).

1278666 is an abundant number, since it is smaller than the sum of its proper divisors (1600296).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1278666 is an frugal number, since it uses more digits than its factorization.

1278666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 897 (or 882 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 1278666 is about 1130.7811459341. The cubic root of 1278666 is about 108.5389724580.

The spelling of 1278666 in words is "one million, two hundred seventy-eight thousand, six hundred sixty-six".