81650 has 24 divisors (see below), whose sum is σ = 160704. Its totient is φ = 30800.

The previous prime is 81649. The next prime is 81667. The reversal of 81650 is 5618.

81650 = T₆₈ + T₆₉ + ... + T₉₂.

It is a hoax number, since the sum of its digits (20) coincides with the sum of the digits of its distinct prime factors.

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

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81650.

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 11 ways as a sum of consecutive naturals, for example, 1115 + ... + 1185.

It is an arithmetic number, because the mean of its divisors is an integer number (6696).

2⁸¹⁶⁵⁰ is an apocalyptic number.

81650 is a deficient number, since it is larger than the sum of its proper divisors (79054).

81650 is a wasteful number, since it uses less digits than its factorization.

81650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 81650 is about 285.7446412446. The cubic root of 81650 is about 43.3829149766.

It can be divided in two parts, 81 and 650, that multiplied together give a triangular number (52650 = T₃₂₄).

The spelling of 81650 in words is "eighty-one thousand, six hundred fifty".