1664239 has 4 divisors (see below), whose sum is σ = 1673056. Its totient is φ = 1655424.

The previous prime is 1664227. The next prime is 1664251. The reversal of 1664239 is 9324661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9324661 = 53 ⋅175937.

It is an interprime number because it is at equal distance from previous prime (1664227) and next prime (1664251).

It is a cyclic number.

It is not a de Polignac number, because 1664239 - 2¹¹ = 1662191 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1664239.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4119 + ... + 4504.

It is an arithmetic number, because the mean of its divisors is an integer number (418264).

2^1664239 is an apocalyptic number.

1664239 is a deficient number, since it is larger than the sum of its proper divisors (8817).

1664239 is an equidigital number, since it uses as much as digits as its factorization.

1664239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8816.

The product of its digits is 7776, while the sum is 31.

The square root of 1664239 is about 1290.0538748440. The cubic root of 1664239 is about 118.5055158346.

The spelling of 1664239 in words is "one million, six hundred sixty-four thousand, two hundred thirty-nine".