1640009 has 4 divisors (see below), whose sum is σ = 1874304. Its totient is φ = 1405716.

The previous prime is 1639999. The next prime is 1640017. The reversal of 1640009 is 9000461.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1640009 - 2¹² = 1635913 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (1640059) 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, 117137 + ... + 117150.

It is an arithmetic number, because the mean of its divisors is an integer number (468576).

2^1640009 is an apocalyptic number.

It is an amenable number.

1640009 is a deficient number, since it is larger than the sum of its proper divisors (234295).

1640009 is an equidigital number, since it uses as much as digits as its factorization.

1640009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234294.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 1640009 is about 1280.6283613914. The cubic root of 1640009 is about 117.9275865198.

The spelling of 1640009 in words is "one million, six hundred forty thousand, nine".