81836 has 12 divisors (see below), whose sum is σ = 147000. Its totient is φ = 39840.

The previous prime is 81817. The next prime is 81839. The reversal of 81836 is 63818.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (81839) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 86 + ... + 413.

It is an arithmetic number, because the mean of its divisors is an integer number (12250).

2⁸¹⁸³⁶ is an apocalyptic number.

It is an amenable number.

81836 is a deficient number, since it is larger than the sum of its proper divisors (65164).

81836 is a wasteful number, since it uses less digits than its factorization.

81836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 544 (or 542 counting only the distinct ones).

The product of its digits is 1152, while the sum is 26.

The square root of 81836 is about 286.0699215227. The cubic root of 81836 is about 43.4158323175.

Subtracting from 81836 its sum of digits (26), we obtain a triangular number (81810 = T₄₀₄).

The spelling of 81836 in words is "eighty-one thousand, eight hundred thirty-six".