30809 has 2 divisors, whose sum is σ = 30810.
Its totient is φ = 30808.
The previous prime is 30803. The next prime is 30817. The reversal of 30809 is 90803.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 29584 + 1225 = 172^2 + 35^2
It is an emirp because it is prime and its reverse (90803) is a distict prime.
It is a cyclic number.
It is not a de Polignac number, because 30809 - 28 = 30553 is a prime.
It is a Chen prime.
It is not a weakly prime, because it can be changed into another prime (30803) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15404 + 15405.
It is an arithmetic number, because the mean of its divisors is an integer number (15405).
230809 is an apocalyptic number.
It is an amenable number.
30809 is a deficient number, since it is larger than the sum of its proper divisors (1).
30809 is an equidigital number, since it uses as much as digits as its factorization.
30809 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 216, while the sum is 20.
The square root of 30809 is about 175.5249270047.
The cubic root of 30809 is about 31.3491570394.
The spelling of 30809 in words is "thirty thousand, eight hundred nine".