129391 has 4 divisors (see below), whose sum is σ = 132192. Its totient is φ = 126592.
The previous prime is 129379. The next prime is 129401. The reversal of 129391 is 193921.
It is a semiprime because it is the product of two primes.
It is a cyclic number.
It is not a de Polignac number, because 129391 - 27 = 129263 is a prime.
It is a Duffinian number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (129341) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1330 + ... + 1423.
It is an arithmetic number, because the mean of its divisors is an integer number (33048).
2129391 is an apocalyptic number.
129391 is the 228-th centered pentagonal number.
129391 is a deficient number, since it is larger than the sum of its proper divisors (2801).
129391 is an equidigital number, since it uses as much as digits as its factorization.
129391 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 2800.
The product of its digits is 486, while the sum is 25.
The square root of 129391 is about 359.7096050983. The cubic root of 129391 is about 50.5787419752.
It can be divided in two parts, 1 and 29391, that added together give a palindrome (29392).
The spelling of 129391 in words is "one hundred twenty-nine thousand, three hundred ninety-one".
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