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20508 = 2231709

20508 has 12 divisors (see below), whose sum is σ = 47880. Its totient is φ = 6832.

The previous prime is 20507. The next prime is 20509. The reversal of 20508 is 80502.

It is an interprime number because it is at equal distance from previous prime (20507) and next prime (20509).

It is a tau number, because it is divible by the number of its divisors (12).

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 843 + ... + 866.

It is an arithmetic number, because the mean of its divisors is an integer number (3990).

220508 is an apocalyptic number.

It is an amenable number.

20508 is an abundant number, since it is smaller than the sum of its proper divisors (27372).

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 (23940).

20508 is a wasteful number, since it uses less digits than its factorization.

20508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1716 (or 1714 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 20508 is about 143.2061451195. The cubic root of 20508 is about 27.3720780435.

It can be divided in two parts, 20 and 508, that added together give a triangular number (528 = T32).

The spelling of 20508 in words is "twenty thousand, five hundred eight".

Divisors: 1 2 3 4 6 12 1709 3418 5127 6836 10254 20508