1809998 has 4 divisors (see below), whose sum is σ = 2715000. Its totient is φ = 904998.

The previous prime is 1809991. The next prime is 1810001. The reversal of 1809998 is 8999081.

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 (1809991) 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 as a sum of consecutive naturals, namely, 452498 + ... + 452501.

It is an arithmetic number, because the mean of its divisors is an integer number (678750).

2^1809998 is an apocalyptic number.

1809998 is a deficient number, since it is larger than the sum of its proper divisors (905002).

1809998 is an equidigital number, since it uses as much as digits as its factorization.

1809998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 905001.

The product of its (nonzero) digits is 46656, while the sum is 44.

The square root of 1809998 is about 1345.3616614130. The cubic root of 1809998 is about 121.8688458869.

The spelling of 1809998 in words is "one million, eight hundred nine thousand, nine hundred ninety-eight".