1998478 has 4 divisors (see below), whose sum is σ = 2997720. Its totient is φ = 999238.

The previous prime is 1998473. The next prime is 1998497. The reversal of 1998478 is 8748991.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1998473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499618 + ... + 499621.

It is an arithmetic number, because the mean of its divisors is an integer number (749430).

2^1998478 is an apocalyptic number.

1998478 is a deficient number, since it is larger than the sum of its proper divisors (999242).

1998478 is an equidigital number, since it uses as much as digits as its factorization.

1998478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 999241.

The product of its digits is 145152, while the sum is 46.

The square root of 1998478 is about 1413.6753516985. The cubic root of 1998478 is about 125.9601368816.

The spelling of 1998478 in words is "one million, nine hundred ninety-eight thousand, four hundred seventy-eight".