81885666 has 8 divisors (see below), whose sum is σ = 163771344. Its totient is φ = 27295220.

The previous prime is 81885659. The next prime is 81885673. The reversal of 81885666 is 66658818.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81885659) and next prime (81885673).

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

81885666 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6823800 + ... + 6823811.

It is an arithmetic number, because the mean of its divisors is an integer number (20471418).

Almost surely, 2^81885666 is an apocalyptic number.

81885666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81885666 is a wasteful number, since it uses less digits than its factorization.

81885666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13647616.

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

The square root of 81885666 is about 9049.0698969563. The cubic root of 81885666 is about 434.2461351672.

The spelling of 81885666 in words is "eighty-one million, eight hundred eighty-five thousand, six hundred sixty-six".