66871081 has 4 divisors (see below), whose sum is σ = 70804692. Its totient is φ = 62937472.

The previous prime is 66871073. The next prime is 66871087. The reversal of 66871081 is 18017866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18017866 = 2 ⋅9008933.

It can be written as a sum of positive squares in 2 ways, for example, as 25847056 + 41024025 = 5084^2 + 6405^2 .

It is a cyclic number.

It is not a de Polignac number, because 66871081 - 2³ = 66871073 is a prime.

It is a super-2 number, since 2×66871081² = 8943482948217122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66871081.

It is not an unprimeable number, because it can be changed into a prime (66871087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1966780 + ... + 1966813.

It is an arithmetic number, because the mean of its divisors is an integer number (17701173).

Almost surely, 2^66871081 is an apocalyptic number.

It is an amenable number.

66871081 is a deficient number, since it is larger than the sum of its proper divisors (3933611).

66871081 is a wasteful number, since it uses less digits than its factorization.

66871081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3933610.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 66871081 is about 8177.4739987358. The cubic root of 66871081 is about 405.8941399368.

The spelling of 66871081 in words is "sixty-six million, eight hundred seventy-one thousand, eighty-one".