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18123481 = 163111187
BaseRepresentation
bin100010100100…
…0101011011001
31021002202202001
41011020223121
514114422411
61444241001
7310022065
oct105105331
937082661
1018123481
11a259492
1260a0161
1339a726c
14259aaa5
1518cedc1
hex1148ad9

18123481 has 4 divisors (see below), whose sum is σ = 18234832. Its totient is φ = 18012132.

The previous prime is 18123467. The next prime is 18123493. The reversal of 18123481 is 18432181.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18123481 - 25 = 18123449 is a prime.

It is a super-2 number, since 2×181234812 = 656921127114722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18123421) 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 3 ways as a sum of consecutive naturals, for example, 55431 + ... + 55756.

It is an arithmetic number, because the mean of its divisors is an integer number (4558708).

Almost surely, 218123481 is an apocalyptic number.

It is an amenable number.

18123481 is a deficient number, since it is larger than the sum of its proper divisors (111351).

18123481 is a wasteful number, since it uses less digits than its factorization.

18123481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111350.

The product of its digits is 1536, while the sum is 28.

The square root of 18123481 is about 4257.1681902410. The cubic root of 18123481 is about 262.6720553047.

The spelling of 18123481 in words is "eighteen million, one hundred twenty-three thousand, four hundred eighty-one".

Divisors: 1 163 111187 18123481