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20475 = 3252713
BaseRepresentation
bin100111111111011
31001002100
410333323
51123400
6234443
7113460
oct47773
931070
1020475
1114424
12ba23
139420
147667
156100
hex4ffb

20475 has 36 divisors (see below), whose sum is σ = 45136. Its totient is φ = 8640.

The previous prime is 20443. The next prime is 20477. The reversal of 20475 is 57402.

It is a happy number.

20475 is nontrivially palindromic in base 14.

20475 is a nontrivial binomial coefficient, being equal to C(28, 4).

It is not a de Polignac number, because 20475 - 25 = 20443 is a prime.

20475 is a lucky number.

It is a nialpdrome in base 13 and base 15.

It is not an unprimeable number, because it can be changed into a prime (20477) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1569 + ... + 1581.

220475 is an apocalyptic number.

20475 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20475 is the 117-th pentagonal number.

20475 is an abundant number, since it is smaller than the sum of its proper divisors (24661).

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 (22568).

20475 is a wasteful number, since it uses less digits than its factorization.

20475 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36 (or 28 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 18.

The square root of 20475 is about 143.0908802125. The cubic root of 20475 is about 27.3573884344.

Adding to 20475 its reverse (57402), we get a palindrome (77877).

The spelling of 20475 in words is "twenty thousand, four hundred seventy-five".

Divisors: 1 3 5 7 9 13 15 21 25 35 39 45 63 65 75 91 105 117 175 195 225 273 315 325 455 525 585 819 975 1365 1575 2275 2925 4095 6825 20475