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18923281 = 134730971
BaseRepresentation
bin100100000101…
…1111100010001
31022121101212021
41020023330101
514321021111
61513331441
7316562626
oct110137421
938541767
1018923281
11a755383
126406b81
133bc7310
14272834d
1519dbd71
hex120bf11

18923281 has 8 divisors (see below), whose sum is σ = 20813184. Its totient is φ = 17095440.

The previous prime is 18923257. The next prime is 18923291. The reversal of 18923281 is 18232981.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18923281 - 27 = 18923153 is a prime.

It is a super-2 number, since 2×189232812 = 716181127609922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18923231) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 14875 + ... + 16096.

It is an arithmetic number, because the mean of its divisors is an integer number (2601648).

Almost surely, 218923281 is an apocalyptic number.

It is an amenable number.

18923281 is a deficient number, since it is larger than the sum of its proper divisors (1889903).

18923281 is a wasteful number, since it uses less digits than its factorization.

18923281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31031.

The product of its digits is 6912, while the sum is 34.

The square root of 18923281 is about 4350.0897691887. The cubic root of 18923281 is about 266.4805275664.

The spelling of 18923281 in words is "eighteen million, nine hundred twenty-three thousand, two hundred eighty-one".

Divisors: 1 13 47 611 30971 402623 1455637 18923281