999605 has 4 divisors (see below), whose sum is σ = 1199532. Its totient is φ = 799680.

The previous prime is 999599. The next prime is 999611. The reversal of 999605 is 506999.

999605 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is an interprime number because it is at equal distance from previous prime (999599) and next prime (999611).

It can be written as a sum of positive squares in 2 ways, for example, as 142129 + 857476 = 377^2 + 926^2 .

It is not a de Polignac number, because 999605 - 2⁶ = 999541 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 999605.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 99956 + ... + 99965.

It is an arithmetic number, because the mean of its divisors is an integer number (299883).

2⁹⁹⁹⁶⁰⁵ is an apocalyptic number.

It is an amenable number.

999605 is a deficient number, since it is larger than the sum of its proper divisors (199927).

999605 is a wasteful number, since it uses less digits than its factorization.

999605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199926.

The product of its (nonzero) digits is 21870, while the sum is 38.

The square root of 999605 is about 999.8024804930. The cubic root of 999605 is about 99.9868315993.

The spelling of 999605 in words is "nine hundred ninety-nine thousand, six hundred five".