1668081 has 4 divisors (see below), whose sum is σ = 2224112. Its totient is φ = 1112052.

The previous prime is 1668061. The next prime is 1668083. The reversal of 1668081 is 1808661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1808661 = 3 ⋅602887.

It is not a de Polignac number, because 1668081 - 2¹⁵ = 1635313 is a prime.

It is a super-2 number, since 2×1668081² = 5564988445122, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1668083) 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, 278011 + ... + 278016.

It is an arithmetic number, because the mean of its divisors is an integer number (556028).

2^1668081 is an apocalyptic number.

It is an amenable number.

1668081 is a deficient number, since it is larger than the sum of its proper divisors (556031).

1668081 is an equidigital number, since it uses as much as digits as its factorization.

1668081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 556030.

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 1668081 is about 1291.5421015205. The cubic root of 1668081 is about 118.5966382192.

Subtracting from 1668081 its sum of digits (30), we obtain a triangular number (1668051 = T₁₈₂₆).

It can be divided in two parts, 16680 and 81, that added together give a palindrome (16761).

The spelling of 1668081 in words is "one million, six hundred sixty-eight thousand, eighty-one".