20986 has 8 divisors (see below), whose sum is σ = 36000. Its totient is φ = 8988.
The previous prime is 20983. The next prime is 21001. The reversal of 20986 is 68902.
It is a sphenic number, since it is the product of 3 distinct primes.
It is a self number, because there is not a number n which added to its sum of digits gives 20986.
It is not an unprimeable number, because it can be changed into a prime (20981) 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, 736 + ... + 763.
It is an arithmetic number, because the mean of its divisors is an integer number (4500).
220986 is an apocalyptic number.
20986 is a deficient number, since it is larger than the sum of its proper divisors (15014).
20986 is a wasteful number, since it uses less digits than its factorization.
20986 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1508.
The product of its (nonzero) digits is 864, while the sum is 25.
The square root of 20986 is about 144.8654548193. The cubic root of 20986 is about 27.5831094583.
The spelling of 20986 in words is "twenty thousand, nine hundred eighty-six".
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