990638 has 16 divisors (see below), whose sum is σ = 1666224. Its totient is φ = 437760.

The previous prime is 990637. The next prime is 990643. The reversal of 990638 is 836099.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 990598 and 990607.

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 990638.

It is not an unprimeable number, because it can be changed into a prime (990631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 206 + ... + 1422.

It is an arithmetic number, because the mean of its divisors is an integer number (104139).

2⁹⁹⁰⁶³⁸ is an apocalyptic number.

990638 is a deficient number, since it is larger than the sum of its proper divisors (675586).

990638 is a wasteful number, since it uses less digits than its factorization.

990638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1267.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 990638 is about 995.3079925330. The cubic root of 990638 is about 99.6869543803.

The spelling of 990638 in words is "nine hundred ninety thousand, six hundred thirty-eight".