1909009 has 4 divisors (see below), whose sum is σ = 1911780. Its totient is φ = 1906240.

The previous prime is 1909003. The next prime is 1909021. The reversal of 1909009 is 9009091.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 1203409 + 705600 = 1097^2 + 840^2 .

It is a cyclic number.

It is not a de Polignac number, because 1909009 - 2¹⁵ = 1876241 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (1909003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 549 + ... + 2029.

It is an arithmetic number, because the mean of its divisors is an integer number (477945).

2^1909009 is an apocalyptic number.

It is an amenable number.

1909009 is a deficient number, since it is larger than the sum of its proper divisors (2771).

1909009 is a wasteful number, since it uses less digits than its factorization.

1909009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2770.

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

The square root of 1909009 is about 1381.6689183737. The cubic root of 1909009 is about 124.0516824103.

The spelling of 1909009 in words is "one million, nine hundred nine thousand, nine".