1666906 has 4 divisors (see below), whose sum is σ = 2500362. Its totient is φ = 833452.

The previous prime is 1666897. The next prime is 1666909. The reversal of 1666906 is 6096661.

It is a happy number.

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., 1666681 + 225 = 1291^2 + 15^2 .

It is a super-2 number, since 2×1666906² = 5557151225672, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1666909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 416725 + ... + 416728.

2^1666906 is an apocalyptic number.

1666906 is a deficient number, since it is larger than the sum of its proper divisors (833456).

1666906 is an equidigital number, since it uses as much as digits as its factorization.

1666906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 833455.

The product of its (nonzero) digits is 11664, while the sum is 34.

The square root of 1666906 is about 1291.0871388098. The cubic root of 1666906 is about 118.5687850989.

The spelling of 1666906 in words is "one million, six hundred sixty-six thousand, nine hundred six".