40018 has 16 divisors (see below), whose sum is σ = 69984.
Its totient is φ = 16960.
The previous prime is 40013. The next prime is 40031. The reversal of 40018 is 81004.
It is a super-4 number, since 4×400184 = 10258444445332899904, which contains 4444 as substring.
40018 is a modest number, since divided by 18 gives 4 as remainder.
It is a plaindrome in base 7 and base 15.
It is not an unprimeable number, because it can be changed into a prime (40013) 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 in 7 ways as a sum of consecutive naturals, for example, 321 + ... + 427.
It is an arithmetic number, because the mean of its divisors is an integer number (4374).
240018 is an apocalyptic number.
40018 is a deficient number, since it is larger than the sum of its proper divisors (29966).
40018 is a wasteful number, since it uses less digits than its factorization.
40018 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 137.
The product of its (nonzero) digits is 32, while the sum is 13.
The square root of 40018 is about 200.0449949386.
The cubic root of 40018 is about 34.2046480921.
The spelling of 40018 in words is "forty thousand, eighteen".