126505409 has 4 divisors (see below), whose sum is σ = 126676416. Its totient is φ = 126334404.

The previous prime is 126505403. The next prime is 126505411. The reversal of 126505409 is 904505621.

It is a happy number.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-126505409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (126505403) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 84389 + ... + 85874.

It is an arithmetic number, because the mean of its divisors is an integer number (31669104).

Almost surely, 2^126505409 is an apocalyptic number.

It is an amenable number.

126505409 is a deficient number, since it is larger than the sum of its proper divisors (171007).

126505409 is an equidigital number, since it uses as much as digits as its factorization.

126505409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171006.

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 126505409 is about 11247.4623360116. The cubic root of 126505409 is about 501.9992076833. Note that the first 3 decimals are identical.

The spelling of 126505409 in words is "one hundred twenty-six million, five hundred five thousand, four hundred nine".