1998105 has 16 divisors (see below), whose sum is σ = 3300864. Its totient is φ = 1031040.

The previous prime is 1998089. The next prime is 1998107. The reversal of 1998105 is 5018991.

It is not a de Polignac number, because 1998105 - 2⁴ = 1998089 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998107) 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 15 ways as a sum of consecutive naturals, for example, 1684 + ... + 2613.

It is an arithmetic number, because the mean of its divisors is an integer number (206304).

2^1998105 is an apocalyptic number.

1998105 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1998105 is a deficient number, since it is larger than the sum of its proper divisors (1302759).

1998105 is a wasteful number, since it uses less digits than its factorization.

1998105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4336.

The product of its (nonzero) digits is 3240, while the sum is 33.

The square root of 1998105 is about 1413.5434199203. The cubic root of 1998105 is about 125.9522999086.

The spelling of 1998105 in words is "one million, nine hundred ninety-eight thousand, one hundred five".