1666667 has 4 divisors (see below), whose sum is σ = 1702176. Its totient is φ = 1631160.

The previous prime is 1666657. The next prime is 1666711. The reversal of 1666667 is 7666661.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1666667 - 2¹² = 1662571 is a prime.

It is a Duffinian number.

It is a plaindrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 1666667.

It is not an unprimeable number, because it can be changed into a prime (1666607) 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 in 3 ways as a sum of consecutive naturals, for example, 17684 + ... + 17777.

It is an arithmetic number, because the mean of its divisors is an integer number (425544).

2^1666667 is an apocalyptic number.

1666667 is a deficient number, since it is larger than the sum of its proper divisors (35509).

1666667 is an equidigital number, since it uses as much as digits as its factorization.

1666667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35508.

The product of its digits is 54432, while the sum is 38.

The square root of 1666667 is about 1290.9945778352. The cubic root of 1666667 is about 118.5631180539.

The spelling of 1666667 in words is "one million, six hundred sixty-six thousand, six hundred sixty-seven".