1664985 has 32 divisors (see below), whose sum is σ = 3094272. Its totient is φ = 748800.

The previous prime is 1664959. The next prime is 1664987. The reversal of 1664985 is 5894661.

It is not a de Polignac number, because 1664985 - 2⁷ = 1664857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1664987) 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 31 ways as a sum of consecutive naturals, for example, 10527 + ... + 10683.

It is an arithmetic number, because the mean of its divisors is an integer number (96696).

2^1664985 is an apocalyptic number.

1664985 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1664985 is a deficient number, since it is larger than the sum of its proper divisors (1429287).

1664985 is a wasteful number, since it uses less digits than its factorization.

1664985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273.

The product of its digits is 51840, while the sum is 39.

The square root of 1664985 is about 1290.3429776614. The cubic root of 1664985 is about 118.5232200042.

It can be divided in two parts, 166 and 4985, that added together give a triangular number (5151 = T₁₀₁).

The spelling of 1664985 in words is "one million, six hundred sixty-four thousand, nine hundred eighty-five".