81002 has 8 divisors (see below), whose sum is σ = 123012.
Its totient is φ = 40000.
The previous prime is 81001. The next prime is 81013. The reversal of 81002 is 20018.
It can be written as a sum of positive squares in 2 ways, for example, as 52441 + 28561 = 229^2 + 169^2
It is a sphenic number, since it is the product of 3 distinct primes.
It is a super-2 number, since 2×810022 = 13122648008, which contains 22 as substring.
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 3 ways as a sum of consecutive naturals, for example, 2 + ... + 402.
281002 is an apocalyptic number.
81002 is a deficient number, since it is larger than the sum of its proper divisors (42010).
81002 is a wasteful number, since it uses less digits than its factorization.
81002 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 504.
The product of its (nonzero) digits is 16, while the sum is 11.
The square root of 81002 is about 284.6085030353.
The cubic root of 81002 is about 43.2678432173.
Adding to 81002 its product of nonzero digits (16), we get a palindrome (81018).
The spelling of 81002 in words is "eighty-one thousand, two".