1388666 has 4 divisors (see below), whose sum is σ = 2083002. Its totient is φ = 694332.

The previous prime is 1388659. The next prime is 1388669. The reversal of 1388666 is 6668831.

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., 863041 + 525625 = 929^2 + 725^2 .

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (1388669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 347165 + ... + 347168.

2^1388666 is an apocalyptic number.

1388666 is a deficient number, since it is larger than the sum of its proper divisors (694336).

1388666 is an equidigital number, since it uses as much as digits as its factorization.

1388666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 694335.

The product of its digits is 41472, while the sum is 38.

The square root of 1388666 is about 1178.4167344365. The cubic root of 1388666 is about 111.5661896611.

The spelling of 1388666 in words is "one million, three hundred eighty-eight thousand, six hundred sixty-six".