1280666 has 4 divisors (see below), whose sum is σ = 1921002. Its totient is φ = 640332.

The previous prime is 1280659. The next prime is 1280677. The reversal of 1280666 is 6660821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1256641 + 24025 = 1121^2 + 155^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320165 + ... + 320168.

2^1280666 is an apocalyptic number.

1280666 is a deficient number, since it is larger than the sum of its proper divisors (640336).

1280666 is an equidigital number, since it uses as much as digits as its factorization.

1280666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 640335.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 1280666 is about 1131.6651448198. The cubic root of 1280666 is about 108.5955326709.

The spelling of 1280666 in words is "one million, two hundred eighty thousand, six hundred sixty-six".