1664659 has 4 divisors (see below), whose sum is σ = 1703416. Its totient is φ = 1625904.

The previous prime is 1664653. The next prime is 1664681. The reversal of 1664659 is 9564661.

1664659 is nontrivially palindromic in base 5.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1664659 - 2³ = 1664651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1664651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19314 + ... + 19399.

It is an arithmetic number, because the mean of its divisors is an integer number (425854).

2^1664659 is an apocalyptic number.

1664659 is a deficient number, since it is larger than the sum of its proper divisors (38757).

1664659 is an equidigital number, since it uses as much as digits as its factorization.

1664659 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38756.

The product of its digits is 38880, while the sum is 37.

The square root of 1664659 is about 1290.2166484742. The cubic root of 1664659 is about 118.5154839802.

The spelling of 1664659 in words is "one million, six hundred sixty-four thousand, six hundred fifty-nine".