666085881 has 4 divisors (see below), whose sum is σ = 888114512. Its totient is φ = 444057252.

The previous prime is 666085841. The next prime is 666085897. The reversal of 666085881 is 188580666.

It is a happy number.

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 666085881 - 2⁶ = 666085817 is a prime.

It is a super-2 number, since 2×666085881² = 887340801735092322, 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 666085881.

It is not an unprimeable number, because it can be changed into a prime (666085841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111014311 + ... + 111014316.

It is an arithmetic number, because the mean of its divisors is an integer number (222028628).

Almost surely, 2^666085881 is an apocalyptic number.

It is an amenable number.

666085881 is a deficient number, since it is larger than the sum of its proper divisors (222028631).

666085881 is a wasteful number, since it uses less digits than its factorization.

666085881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222028630.

The product of its (nonzero) digits is 552960, while the sum is 48.

The square root of 666085881 is about 25808.6396580680. The cubic root of 666085881 is about 873.3267095270.

The spelling of 666085881 in words is "six hundred sixty-six million, eighty-five thousand, eight hundred eighty-one".