1990009 has 8 divisors (see below), whose sum is σ = 2352960. Its totient is φ = 1646736.

The previous prime is 1990007. The next prime is 1990031. The reversal of 1990009 is 9000991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1990009 - 2¹ = 1990007 is a prime.

It is a Duffinian number.

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 7 ways as a sum of consecutive naturals, for example, 4699 + ... + 5104.

It is an arithmetic number, because the mean of its divisors is an integer number (294120).

2^1990009 is an apocalyptic number.

It is an amenable number.

1990009 is a deficient number, since it is larger than the sum of its proper divisors (362951).

1990009 is an equidigital number, since it uses as much as digits as its factorization.

1990009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9839.

The product of its (nonzero) digits is 729, while the sum is 28.

The square root of 1990009 is about 1410.6767879284. The cubic root of 1990009 is about 125.7819568148.

It can be divided in two parts, 19 and 90009, that multiplied together give a palindrome (1710171).

The spelling of 1990009 in words is "one million, nine hundred ninety thousand, nine".