81655 has 8 divisors (see below), whose sum is σ = 112032. Its totient is φ = 55968.

The previous prime is 81649. The next prime is 81667. The reversal of 81655 is 55618.

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

It is a cyclic number.

It is not a de Polignac number, because 81655 - 2³ = 81647 is a prime.

It is a super-3 number, since 3×81655³ = 1633313697259125, which contains 333 as substring.

It is a Duffinian number.

81655 is a lucky number.

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, 1132 + ... + 1201.

It is an arithmetic number, because the mean of its divisors is an integer number (14004).

2⁸¹⁶⁵⁵ is an apocalyptic number.

81655 is a deficient number, since it is larger than the sum of its proper divisors (30377).

81655 is a wasteful number, since it uses less digits than its factorization.

81655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2345.

The product of its digits is 1200, while the sum is 25.

The square root of 81655 is about 285.7533901811. The cubic root of 81655 is about 43.3838005048.

The spelling of 81655 in words is "eighty-one thousand, six hundred fifty-five".