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21706 = 210853
BaseRepresentation
bin101010011001010
31002202221
411103022
51143311
6244254
7120166
oct52312
932687
1021706
1115343
121068a
139b59
147ca6
156671
hex54ca

21706 has 4 divisors (see below), whose sum is σ = 32562. Its totient is φ = 10852.

The previous prime is 21701. The next prime is 21713. The reversal of 21706 is 60712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 18225 + 3481 = 135^2 + 59^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21706.

It is not an unprimeable number, because it can be changed into a prime (21701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5425 + ... + 5428.

221706 is an apocalyptic number.

21706 is a deficient number, since it is larger than the sum of its proper divisors (10856).

21706 is a wasteful number, since it uses less digits than its factorization.

21706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10855.

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 21706 is about 147.3295625460. The cubic root of 21706 is about 27.8950150179.

It can be divided in two parts, 21 and 706, that added together give a palindrome (727).

The spelling of 21706 in words is "twenty-one thousand, seven hundred six".

Divisors: 1 2 10853 21706