990605 has 32 divisors (see below), whose sum is σ = 1548288. Its totient is φ = 590400.

The previous prime is 990599. The next prime is 990631. The reversal of 990605 is 506099.

It is not a de Polignac number, because 990605 - 2⁴ = 990589 is a prime.

It is a Smith number, since the sum of its digits (29) 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 an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11894 + ... + 11976.

It is an arithmetic number, because the mean of its divisors is an integer number (48384).

2⁹⁹⁰⁶⁰⁵ is an apocalyptic number.

It is an amenable number.

990605 is a deficient number, since it is larger than the sum of its proper divisors (557683).

990605 is a wasteful number, since it uses less digits than its factorization.

990605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137.

The product of its (nonzero) digits is 2430, while the sum is 29.

The square root of 990605 is about 995.2914146118. The cubic root of 990605 is about 99.6858474486.

The spelling of 990605 in words is "nine hundred ninety thousand, six hundred five".