1990000 has 50 divisors (see below), whose sum is σ = 4842200. Its totient is φ = 792000.

The previous prime is 1989989. The next prime is 1990007. The reversal of 1990000 is 991.

It is a tau number, because it is divible by the number of its divisors (50).

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 1990000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1990007) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 9901 + ... + 10099.

It is an arithmetic number, because the mean of its divisors is an integer number (96844).

2^1990000 is an apocalyptic number.

1990000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1990000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2421100).

1990000 is an abundant number, since it is smaller than the sum of its proper divisors (2852200).

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

1990000 is an equidigital number, since it uses as much as digits as its factorization.

1990000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227 (or 206 counting only the distinct ones).

The product of its (nonzero) digits is 81, while the sum is 19.

The square root of 1990000 is about 1410.6735979666. The cubic root of 1990000 is about 125.7817671944.

Adding to 1990000 its reverse (991), we get a palindrome (1990991).

The spelling of 1990000 in words is "one million, nine hundred ninety thousand".