40309 has 4 divisors (see below), whose sum is σ = 40716. Its totient is φ = 39904.
The previous prime is 40289. The next prime is 40343. The reversal of 40309 is 90304.
40309 is nontrivially palindromic in base 12.
It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.
It can be written as a sum of positive squares in 2 ways, for example, as 23409 + 16900 = 153^2 + 130^2 .
It is a cyclic number.
It is not a de Polignac number, because 40309 - 25 = 40277 is a prime.
It is a Duffinian number.
40309 is a lucky number.
It is a junction number, because it is equal to n+sod(n) for n = 40292 and 40301.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (40009) by changing a digit.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57 + ... + 289.
It is an arithmetic number, because the mean of its divisors is an integer number (10179).
240309 is an apocalyptic number.
It is an amenable number.
40309 is a deficient number, since it is larger than the sum of its proper divisors (407).
40309 is a wasteful number, since it uses less digits than its factorization.
40309 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 406.
The product of its (nonzero) digits is 108, while the sum is 16.
The square root of 40309 is about 200.7710138441. The cubic root of 40309 is about 34.2873568988.
The spelling of 40309 in words is "forty thousand, three hundred nine".
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