1000665 has 24 divisors (see below), whose sum is σ = 1784328. Its totient is φ = 518400.

The previous prime is 1000651. The next prime is 1000667. The reversal of 1000665 is 5660001.

1000665 is a `hidden beast` number, since 1 + 0 + 0 + 0 + 665 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 451584 + 549081 = 672^2 + 741^2 .

It is not a de Polignac number, because 1000665 - 2⁷ = 1000537 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1000667) 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 23 ways as a sum of consecutive naturals, for example, 1365 + ... + 1965.

It is an arithmetic number, because the mean of its divisors is an integer number (74347).

2^1000665 is an apocalyptic number.

1000665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1000665 is a deficient number, since it is larger than the sum of its proper divisors (783663).

1000665 is a wasteful number, since it uses less digits than its factorization.

1000665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 649 (or 646 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 1000665 is about 1000.3324447402. The cubic root of 1000665 is about 100.0221617549.

Adding to 1000665 its reverse (5660001), we get a palindrome (6660666).

The spelling of 1000665 in words is "one million, six hundred sixty-five", and thus it is an aban number.