1998538 has 4 divisors (see below), whose sum is σ = 2997810. Its totient is φ = 999268.

The previous prime is 1998533. The next prime is 1998541. The reversal of 1998538 is 8358991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8358991 = 541 ⋅15451.

It can be written as a sum of positive squares in only one way, i.e., 1912689 + 85849 = 1383^2 + 293^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1998494 and 1998503.

It is not an unprimeable number, because it can be changed into a prime (1998533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499633 + ... + 499636.

2^1998538 is an apocalyptic number.

1998538 is a deficient number, since it is larger than the sum of its proper divisors (999272).

1998538 is an equidigital number, since it uses as much as digits as its factorization.

1998538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 999271.

The product of its digits is 77760, while the sum is 43.

The square root of 1998538 is about 1413.6965728189. The cubic root of 1998538 is about 125.9613974296.

The spelling of 1998538 in words is "one million, nine hundred ninety-eight thousand, five hundred thirty-eight".