81666382 has 16 divisors (see below), whose sum is σ = 140169312. Its totient is φ = 34957440.

The previous prime is 81666379. The next prime is 81666413. The reversal of 81666382 is 28366618.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10282 + ... + 16402.

It is an arithmetic number, because the mean of its divisors is an integer number (8760582).

Almost surely, 2^81666382 is an apocalyptic number.

81666382 is a deficient number, since it is larger than the sum of its proper divisors (58502930).

81666382 is a wasteful number, since it uses less digits than its factorization.

81666382 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7083.

The product of its digits is 82944, while the sum is 40.

The square root of 81666382 is about 9036.9453910046. The cubic root of 81666382 is about 433.8581618657.

The spelling of 81666382 in words is "eighty-one million, six hundred sixty-six thousand, three hundred eighty-two".