66086861 has 4 divisors (see below), whose sum is σ = 66829500. Its totient is φ = 65344224.

The previous prime is 66086849. The next prime is 66086869. The reversal of 66086861 is 16868066.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 41036836 + 25050025 = 6406^2 + 5005^2 .

It is a cyclic number.

It is not a de Polignac number, because 66086861 - 2¹⁰ = 66085837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66086869) 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, 371186 + ... + 371363.

It is an arithmetic number, because the mean of its divisors is an integer number (16707375).

Almost surely, 2^66086861 is an apocalyptic number.

It is an amenable number.

66086861 is a deficient number, since it is larger than the sum of its proper divisors (742639).

66086861 is an equidigital number, since it uses as much as digits as its factorization.

66086861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 742638.

The product of its (nonzero) digits is 82944, while the sum is 41.

The square root of 66086861 is about 8129.3825718808. The cubic root of 66086861 is about 404.3012102792.

The spelling of 66086861 in words is "sixty-six million, eighty-six thousand, eight hundred sixty-one".