81630 has 24 divisors (see below), whose sum is σ = 212472. Its totient is φ = 21744.
The previous prime is 81629. The next prime is 81637. The reversal of 81630 is 3618.
It is a Harshad number since it is a multiple of its sum of digits (18).
It is an alternating number because its digits alternate between even and odd.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (81637) by changing a digit.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 364 + ... + 543.
It is an arithmetic number, because the mean of its divisors is an integer number (8853).
281630 is an apocalyptic number.
81630 is an abundant number, since it is smaller than the sum of its proper divisors (130842).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106236).
81630 is a wasteful number, since it uses less digits than its factorization.
81630 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 920 (or 917 counting only the distinct ones).
The product of its (nonzero) digits is 144, while the sum is 18.
The square root of 81630 is about 285.7096428194. The cubic root of 81630 is about 43.3793725020.
The spelling of 81630 in words is "eighty-one thousand, six hundred thirty".
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