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18317681 is a prime number
BaseRepresentation
bin100010111100…
…0000101110001
31021110122010122
41011320011301
514142131211
61452340025
7311461214
oct105700561
937418118
1018317681
11a381388
126174615
133a44785
14260b77b
15191c6db
hex1178171

18317681 has 2 divisors, whose sum is σ = 18317682. Its totient is φ = 18317680.

The previous prime is 18317609. The next prime is 18317707. The reversal of 18317681 is 18671381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16974400 + 1343281 = 4120^2 + 1159^2 .

It is an emirp because it is prime and its reverse (18671381) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-18317681 is a prime.

It is a super-2 number, since 2×183176812 = 671074874435522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18317581) 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 as a sum of consecutive naturals, namely, 9158840 + 9158841.

It is an arithmetic number, because the mean of its divisors is an integer number (9158841).

Almost surely, 218317681 is an apocalyptic number.

It is an amenable number.

18317681 is a deficient number, since it is larger than the sum of its proper divisors (1).

18317681 is an equidigital number, since it uses as much as digits as its factorization.

18317681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 35.

The square root of 18317681 is about 4279.9160038487. The cubic root of 18317681 is about 263.6069343830.

The spelling of 18317681 in words is "eighteen million, three hundred seventeen thousand, six hundred eighty-one".