1309 has 8 divisors (see below), whose sum is σ = 1728. Its totient is φ = 960.
The previous prime is 1307. The next prime is 1319. The reversal of 1309 is 9031.
It is a happy number.
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 1309 - 21 = 1307 is a prime.
It is a Duffinian number.
1309 is a lucky number.
It is a plaindrome in base 13.
It is a nialpdrome in base 11 and base 12.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (1301) by changing a digit.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69 + ... + 85.
It is an arithmetic number, because the mean of its divisors is an integer number (216).
It is an amenable number.
1309 is a deficient number, since it is larger than the sum of its proper divisors (419).
1309 is a wasteful number, since it uses less digits than its factorization.
1309 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 35.
The product of its (nonzero) digits is 27, while the sum is 13.
The square root of 1309 is about 36.1801050303. The cubic root of 1309 is about 10.9390569212.
Subtracting from 1309 its sum of digits (13), we obtain a 4-th power (1296 = 64).
The spelling of 1309 in words is "one thousand, three hundred nine".
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