81004 has 24 divisors (see below), whose sum is σ = 177408.
Its totient is φ = 31440.
The previous prime is 81001. The next prime is 81013. The reversal of 81004 is 40018.
It can be divided in two parts, 8100 and 4, that multiplied together give a square (32400 = 1802).
It is a pancake number, because a pancake can be divided into 81004 parts by 402 straight cuts.
It is not an unprimeable number, because it can be changed into a prime (81001) by changing a digit.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 177 + ... + 439.
It is an arithmetic number, because the mean of its divisors is an integer number (7392).
281004 is an apocalyptic number.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 81004, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88704).
81004 is an abundant number, since it is smaller than the sum of its proper divisors (96404).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
81004 is a wasteful number, since it uses less digits than its factorization.
81004 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 285 (or 283 counting only the distinct ones).
The product of its (nonzero) digits is 32, while the sum is 13.
The square root of 81004 is about 284.6120166121.
The cubic root of 81004 is about 43.2681993195.
The spelling of 81004 in words is "eighty-one thousand, four".