208931 has 2 divisors, whose sum is σ = 208932. Its totient is φ = 208930.

The previous prime is 208927. The next prime is 208933. The reversal of 208931 is 139802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 208931 - 2² = 208927 is a prime.

It is a super-2 number, since 2×208931² = 87304325522, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 208933, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 208897 and 208906.

It is not a weakly prime, because it can be changed into another prime (208933) 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 as a sum of consecutive naturals, namely, 104465 + 104466.

It is an arithmetic number, because the mean of its divisors is an integer number (104466).

2²⁰⁸⁹³¹ is an apocalyptic number.

208931 is a deficient number, since it is larger than the sum of its proper divisors (1).

208931 is an equidigital number, since it uses as much as digits as its factorization.

208931 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 208931 is about 457.0897067316. The cubic root of 208931 is about 59.3381899264.

The spelling of 208931 in words is "two hundred eight thousand, nine hundred thirty-one".