126409 has 4 divisors (see below), whose sum is σ = 128016. Its totient is φ = 124804.

The previous prime is 126397. The next prime is 126421. The reversal of 126409 is 904621.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (126397) and next prime (126421).

It is a cyclic number.

It is not a de Polignac number, because 126409 - 2⁹ = 125897 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 126409.

It is not an unprimeable number, because it can be changed into a prime (126499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 679 + ... + 844.

It is an arithmetic number, because the mean of its divisors is an integer number (32004).

2¹²⁶⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

126409 is a deficient number, since it is larger than the sum of its proper divisors (1607).

126409 is an equidigital number, since it uses as much as digits as its factorization.

126409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1606.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 126409 is about 355.5404337062. The cubic root of 126409 is about 50.1871651764.

It can be divided in two parts, 126 and 409, that added together give a palindrome (535).

The spelling of 126409 in words is "one hundred twenty-six thousand, four hundred nine".