1665566 has 16 divisors (see below), whose sum is σ = 2872320. Its totient is φ = 709560.

The previous prime is 1665563. The next prime is 1665569. The reversal of 1665566 is 6655661.

It is an interprime number because it is at equal distance from previous prime (1665563) and next prime (1665569).

It is a super-2 number, since 2×1665566² = 5548220200712, which contains 22 as substring.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3575 + ... + 4013.

It is an arithmetic number, because the mean of its divisors is an integer number (179520).

2^1665566 is an apocalyptic number.

1665566 is a deficient number, since it is larger than the sum of its proper divisors (1206754).

1665566 is a wasteful number, since it uses less digits than its factorization.

1665566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 719.

The product of its digits is 32400, while the sum is 35.

The square root of 1665566 is about 1290.5680919657. The cubic root of 1665566 is about 118.5370047095.

The spelling of 1665566 in words is "one million, six hundred sixty-five thousand, five hundred sixty-six".