1664005 has 8 divisors (see below), whose sum is σ = 2282112. Its totient is φ = 1141008.

The previous prime is 1663997. The next prime is 1664009. The reversal of 1664005 is 5004661.

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

It is a cyclic number.

It is not a de Polignac number, because 1664005 - 2³ = 1663997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664009) 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, 23737 + ... + 23806.

It is an arithmetic number, because the mean of its divisors is an integer number (285264).

2^1664005 is an apocalyptic number.

It is an amenable number.

1664005 is a deficient number, since it is larger than the sum of its proper divisors (618107).

1664005 is an equidigital number, since it uses as much as digits as its factorization.

1664005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47555.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 1664005 is about 1289.9631777690. The cubic root of 1664005 is about 118.4999614259.

Adding to 1664005 its reverse (5004661), we get a palindrome (6668666).

The spelling of 1664005 in words is "one million, six hundred sixty-four thousand, five".