66081 has 4 divisors (see below), whose sum is σ = 88112. Its totient is φ = 44052.

The previous prime is 66071. The next prime is 66083. The reversal of 66081 is 18066.

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.

It is not a de Polignac number, because 66081 - 2¹¹ = 64033 is a prime.

It is a super-2 number, since 2×66081² = 8733397122, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

66081 is a modest number, since divided by 81 gives 66 as remainder.

It is not an unprimeable number, because it can be changed into a prime (66083) 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, 11011 + ... + 11016.

It is an arithmetic number, because the mean of its divisors is an integer number (22028).

2⁶⁶⁰⁸¹ is an apocalyptic number.

It is an amenable number.

66081 is a deficient number, since it is larger than the sum of its proper divisors (22031).

66081 is a wasteful number, since it uses less digits than its factorization.

66081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22030.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 66081 is about 257.0622492705. The cubic root of 66081 is about 40.4289257931.

It can be divided in two parts, 660 and 81, that added together give a triangular number (741 = T₃₈).

The spelling of 66081 in words is "sixty-six thousand, eighty-one".