1811998 has 4 divisors (see below), whose sum is σ = 2718000. Its totient is φ = 905998.

The previous prime is 1811993. The next prime is 1812037. The reversal of 1811998 is 8991181.

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 (1811993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 452998 + ... + 453001.

It is an arithmetic number, because the mean of its divisors is an integer number (679500).

2^1811998 is an apocalyptic number.

1811998 is a deficient number, since it is larger than the sum of its proper divisors (906002).

1811998 is an equidigital number, since it uses as much as digits as its factorization.

1811998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 906001.

The product of its digits is 5184, while the sum is 37.

The square root of 1811998 is about 1346.1047507531. The cubic root of 1811998 is about 121.9137166496.

It can be divided in two parts, 1811 and 998, that added together give a square (2809 = 53²).

The spelling of 1811998 in words is "one million, eight hundred eleven thousand, nine hundred ninety-eight".