1666705 has 4 divisors (see below), whose sum is σ = 2000052. Its totient is φ = 1333360.

The previous prime is 1666657. The next prime is 1666711. The reversal of 1666705 is 5076661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5076661 = 41 ⋅123821.

It can be written as a sum of positive squares in 2 ways, for example, as 690561 + 976144 = 831^2 + 988^2 .

It is not a de Polignac number, because 1666705 - 2¹³ = 1658513 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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, 166666 + ... + 166675.

It is an arithmetic number, because the mean of its divisors is an integer number (500013).

2^1666705 is an apocalyptic number.

It is an amenable number.

1666705 is a deficient number, since it is larger than the sum of its proper divisors (333347).

1666705 is an equidigital number, since it uses as much as digits as its factorization.

1666705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333346.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 1666705 is about 1291.0092950866. The cubic root of 1666705 is about 118.5640191265.

The spelling of 1666705 in words is "one million, six hundred sixty-six thousand, seven hundred five".