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42561 = 324729
BaseRepresentation
bin1010011001000001
32011101100
422121001
52330221
6525013
7235041
oct123101
964340
1042561
1129a82
1220769
13164ac
1411721
15c926
hexa641

42561 has 6 divisors (see below), whose sum is σ = 61490. Its totient is φ = 28368.

The previous prime is 42557. The next prime is 42569. The reversal of 42561 is 16524.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 24336 + 18225 = 156^2 + 135^2 .

It is not a de Polignac number, because 42561 - 22 = 42557 is a prime.

It is a super-2 number, since 2×425612 = 3622877442, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

42561 is a lucky number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (42569) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2356 + ... + 2373.

242561 is an apocalyptic number.

It is an amenable number.

42561 is a deficient number, since it is larger than the sum of its proper divisors (18929).

42561 is a wasteful number, since it uses less digits than its factorization.

42561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4735 (or 4732 counting only the distinct ones).

The product of its digits is 240, while the sum is 18.

The square root of 42561 is about 206.3031749635. The cubic root of 42561 is about 34.9143483884.

The spelling of 42561 in words is "forty-two thousand, five hundred sixty-one".

Divisors: 1 3 9 4729 14187 42561