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21687168 = 27356477
BaseRepresentation
bin101001010111…
…0101110000000
31111210211012110
41102232232000
521022442133
62052455320
7352223616
oct122565600
944724173
1021687168
1111272988
12731a540
134654359
142c476b6
151d85c63
hex14aeb80

21687168 has 32 divisors (see below), whose sum is σ = 57607560. Its totient is φ = 7228928.

The previous prime is 21687119. The next prime is 21687191. The reversal of 21687168 is 86178612.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27855 + ... + 28622.

Almost surely, 221687168 is an apocalyptic number.

It is an amenable number.

21687168 is an abundant number, since it is smaller than the sum of its proper divisors (35920392).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21687168 is an equidigital number, since it uses as much as digits as its factorization.

21687168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56494 (or 56482 counting only the distinct ones).

The product of its digits is 32256, while the sum is 39.

The square root of 21687168 is about 4656.9483570252. The cubic root of 21687168 is about 278.8694549919.

The spelling of 21687168 in words is "twenty-one million, six hundred eighty-seven thousand, one hundred sixty-eight".

Divisors: 1 2 3 4 6 8 12 16 24 32 48 64 96 128 192 384 56477 112954 169431 225908 338862 451816 677724 903632 1355448 1807264 2710896 3614528 5421792 7229056 10843584 21687168