6664081 has 4 divisors (see below), whose sum is σ = 6730164. Its totient is φ = 6598000.

The previous prime is 6664069. The next prime is 6664087. The reversal of 6664081 is 1804666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1804666 = 2 ⋅902333.

It can be written as a sum of positive squares in 2 ways, for example, as 5958481 + 705600 = 2441^2 + 840^2 .

It is a cyclic number.

It is not a de Polignac number, because 6664081 - 2¹³ = 6655889 is a prime.

It is a super-2 number, since 2×6664081² = 88819951149122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6664087) 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, 32890 + ... + 33091.

It is an arithmetic number, because the mean of its divisors is an integer number (1682541).

Almost surely, 2^6664081 is an apocalyptic number.

It is an amenable number.

6664081 is a deficient number, since it is larger than the sum of its proper divisors (66083).

6664081 is a wasteful number, since it uses less digits than its factorization.

6664081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66082.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 6664081 is about 2581.4881367149. The cubic root of 6664081 is about 188.1828705749.

It can be divided in two parts, 666 and 4081, that multiplied together give a triangular number (2717946 = T₂₃₃₁).

The spelling of 6664081 in words is "six million, six hundred sixty-four thousand, eighty-one".