1999818 has 24 divisors (see below), whose sum is σ = 4360356. Its totient is φ = 662400.

The previous prime is 1999817. The next prime is 1999819. The reversal of 1999818 is 8189991.

It is an interprime number because it is at equal distance from previous prime (1999817) and next prime (1999819).

It can be written as a sum of positive squares in 2 ways, for example, as 1996569 + 3249 = 1413^2 + 57^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1999817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4108 + ... + 4568.

2^1999818 is an apocalyptic number.

1999818 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1999818 is an abundant number, since it is smaller than the sum of its proper divisors (2360538).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1999818 is a wasteful number, since it uses less digits than its factorization.

1999818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 710 (or 707 counting only the distinct ones).

The product of its digits is 46656, while the sum is 45.

The square root of 1999818 is about 1414.1492141921. The cubic root of 1999818 is about 125.9882831130.

The spelling of 1999818 in words is "one million, nine hundred ninety-nine thousand, eight hundred eighteen".