66643081 has 8 divisors (see below), whose sum is σ = 68733000. Its totient is φ = 64575360.

The previous prime is 66643067. The next prime is 66643103. The reversal of 66643081 is 18034666.

It can be written as a sum of positive squares in 4 ways, for example, as 3980025 + 62663056 = 1995^2 + 7916^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66643081 - 2¹⁷ = 66512009 is a prime.

It is a super-2 number, since 2×66643081² = 8882600490345122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66643061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 655 + ... + 11563.

It is an arithmetic number, because the mean of its divisors is an integer number (8591625).

Almost surely, 2^66643081 is an apocalyptic number.

It is an amenable number.

66643081 is a deficient number, since it is larger than the sum of its proper divisors (2089919).

66643081 is a wasteful number, since it uses less digits than its factorization.

66643081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11099.

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 66643081 is about 8163.5213602954. The cubic root of 66643081 is about 405.4323098018.

The spelling of 66643081 in words is "sixty-six million, six hundred forty-three thousand, eighty-one".