81086660 has 24 divisors (see below), whose sum is σ = 170784600. Its totient is φ = 32338944.

The previous prime is 81086641. The next prime is 81086711. The reversal of 81086660 is 6668018.

It can be written as a sum of positive squares in 4 ways, for example, as 10291264 + 70795396 = 3208^2 + 8414^2 .

It is a nialpdrome in base 14.

It is a self number, because there is not a number n which added to its sum of digits gives 81086660.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1172 + ... + 12788.

It is an arithmetic number, because the mean of its divisors is an integer number (7116025).

Almost surely, 2^81086660 is an apocalyptic number.

It is an amenable number.

81086660 is an abundant number, since it is smaller than the sum of its proper divisors (89697940).

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

81086660 is a wasteful number, since it uses less digits than its factorization.

81086660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11975 (or 11973 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 81086660 is about 9004.8131574175. The cubic root of 81086660 is about 432.8291189950.

The spelling of 81086660 in words is "eighty-one million, eighty-six thousand, six hundred sixty".