1664885 has 8 divisors (see below), whose sum is σ = 2005080. Its totient is φ = 1327104.

The previous prime is 1664869. The next prime is 1664893. The reversal of 1664885 is 5884661.

It can be written as a sum of positive squares in 4 ways, for example, as 3364 + 1661521 = 58^2 + 1289^2 .

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 1664885 - 2⁴ = 1664869 is a prime.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 1781 + ... + 2549.

It is an arithmetic number, because the mean of its divisors is an integer number (250635).

2^1664885 is an apocalyptic number.

It is an amenable number.

1664885 is a deficient number, since it is larger than the sum of its proper divisors (340195).

1664885 is an equidigital number, since it uses as much as digits as its factorization.

1664885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1207.

The product of its digits is 46080, while the sum is 38.

The square root of 1664885 is about 1290.3042276921. The cubic root of 1664885 is about 118.5208470981.

The spelling of 1664885 in words is "one million, six hundred sixty-four thousand, eight hundred eighty-five".