1666605 has 16 divisors (see below), whose sum is σ = 2689344. Its totient is φ = 881280.

The previous prime is 1666597. The next prime is 1666607. The reversal of 1666605 is 5066661.

1666605 is nontrivially palindromic in base 14.

It is not a de Polignac number, because 1666605 - 2³ = 1666597 is a prime.

1666605 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666607) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1650 + ... + 2460.

It is an arithmetic number, because the mean of its divisors is an integer number (168084).

2^1666605 is an apocalyptic number.

1666605 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1666605 is a deficient number, since it is larger than the sum of its proper divisors (1022739).

1666605 is a wasteful number, since it uses less digits than its factorization.

1666605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 956.

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 1666605 is about 1290.9705651176. The cubic root of 1666605 is about 118.5616478533.

The spelling of 1666605 in words is "one million, six hundred sixty-six thousand, six hundred five".