100391 has 2 divisors, whose sum is σ = 100392. Its totient is φ = 100390.
The previous prime is 100379. The next prime is 100393. The reversal of 100391 is 193001.
100391 is an esthetic number in base 7, because in such base its adjacent digits differ by 1.
It is a strong prime.
It is a cyclic number.
It is not a de Polignac number, because 100391 - 210 = 99367 is a prime.
Together with 100393, it forms a pair of twin primes.
It is a Chen prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (100393) 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, 50195 + 50196.
It is an arithmetic number, because the mean of its divisors is an integer number (50196).
2100391 is an apocalyptic number.
100391 is a deficient number, since it is larger than the sum of its proper divisors (1).
100391 is an equidigital number, since it uses as much as digits as its factorization.
100391 is an odious number, because the sum of its binary digits is odd.
The product of its (nonzero) digits is 27, while the sum is 14.
The square root of 100391 is about 316.8453881627. The cubic root of 100391 is about 46.4763050358.
Adding to 100391 its reverse (193001), we get a palindrome (293392).
The spelling of 100391 in words is "one hundred thousand, three hundred ninety-one".
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