1668505 has 4 divisors (see below), whose sum is σ = 2002212. Its totient is φ = 1334800.

The previous prime is 1668503. The next prime is 1668509. The reversal of 1668505 is 5058661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5058661 = 1933 ⋅2617.

It can be written as a sum of positive squares in 2 ways, for example, as 1172889 + 495616 = 1083^2 + 704^2 .

It is not a de Polignac number, because 1668505 - 2¹ = 1668503 is a prime.

It is a Duffinian number.

1668505 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1668503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166846 + ... + 166855.

It is an arithmetic number, because the mean of its divisors is an integer number (500553).

2^1668505 is an apocalyptic number.

It is an amenable number.

1668505 is a deficient number, since it is larger than the sum of its proper divisors (333707).

1668505 is an equidigital number, since it uses as much as digits as its factorization.

1668505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333706.

The product of its (nonzero) digits is 7200, while the sum is 31.

The square root of 1668505 is about 1291.7062359531. The cubic root of 1668505 is about 118.6066858358.

The spelling of 1668505 in words is "one million, six hundred sixty-eight thousand, five hundred five".