126391 has 4 divisors (see below), whose sum is σ = 127792. Its totient is φ = 124992.

The previous prime is 126359. The next prime is 126397. The reversal of 126391 is 193621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 193621 = 37 ⋅5233.

It is a cyclic number.

It is not a de Polignac number, because 126391 - 2⁵ = 126359 is a prime.

It is a Duffinian number.

It is a plaindrome in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (126397) 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, 555 + ... + 748.

It is an arithmetic number, because the mean of its divisors is an integer number (31948).

2¹²⁶³⁹¹ is an apocalyptic number.

126391 is a deficient number, since it is larger than the sum of its proper divisors (1401).

126391 is an equidigital number, since it uses as much as digits as its factorization.

126391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1400.

The product of its digits is 324, while the sum is 22.

The square root of 126391 is about 355.5151192284. The cubic root of 126391 is about 50.1847829308.

The spelling of 126391 in words is "one hundred twenty-six thousand, three hundred ninety-one".