123936409 has 4 divisors (see below), whose sum is σ = 131226804. Its totient is φ = 116646016.

The previous prime is 123936391. The next prime is 123936427. The reversal of 123936409 is 904639321.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (123936391) and next prime (123936427).

It can be written as a sum of positive squares in 2 ways, for example, as 114918400 + 9018009 = 10720^2 + 3003^2 .

It is a cyclic number.

It is not a de Polignac number, because 123936409 - 2⁹ = 123935897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123936469) 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, 3645172 + ... + 3645205.

It is an arithmetic number, because the mean of its divisors is an integer number (32806701).

Almost surely, 2^123936409 is an apocalyptic number.

It is an amenable number.

123936409 is a deficient number, since it is larger than the sum of its proper divisors (7290395).

123936409 is an equidigital number, since it uses as much as digits as its factorization.

123936409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7290394.

The product of its (nonzero) digits is 34992, while the sum is 37.

The square root of 123936409 is about 11132.6730393019. The cubic root of 123936409 is about 498.5778374090.

It can be divided in two parts, 1239 and 36409, that multiplied together give a triangular number (45110751 = T₉₄₉₈).

The spelling of 123936409 in words is "one hundred twenty-three million, nine hundred thirty-six thousand, four hundred nine".