1998445 has 4 divisors (see below), whose sum is σ = 2398140. Its totient is φ = 1598752.

The previous prime is 1998443. The next prime is 1998449. The reversal of 1998445 is 5448991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5448991 = 19 ⋅286789.

It can be written as a sum of positive squares in 2 ways, for example, as 527076 + 1471369 = 726^2 + 1213^2 .

It is a cyclic number.

It is not a de Polignac number, because 1998445 - 2¹ = 1998443 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1998398 and 1998407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 199840 + ... + 199849.

It is an arithmetic number, because the mean of its divisors is an integer number (599535).

2^1998445 is an apocalyptic number.

It is an amenable number.

1998445 is a deficient number, since it is larger than the sum of its proper divisors (399695).

1998445 is an equidigital number, since it uses as much as digits as its factorization.

1998445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399694.

The product of its digits is 51840, while the sum is 40.

The square root of 1998445 is about 1413.6636799465. The cubic root of 1998445 is about 125.9594435694.

The spelling of 1998445 in words is "one million, nine hundred ninety-eight thousand, four hundred forty-five".