400009123 has 4 divisors (see below), whose sum is σ = 417400848. Its totient is φ = 382617400.

The previous prime is 400009097. The next prime is 400009163. The reversal of 400009123 is 321900004.

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 400009123 - 2⁹ = 400008611 is a prime.

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 400009123.

It is not an unprimeable number, because it can be changed into a prime (400009163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8695828 + ... + 8695873.

It is an arithmetic number, because the mean of its divisors is an integer number (104350212).

Almost surely, 2^400009123 is an apocalyptic number.

400009123 is a deficient number, since it is larger than the sum of its proper divisors (17391725).

400009123 is a wasteful number, since it uses less digits than its factorization.

400009123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17391724.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 400009123 is about 20000.2280736996. The cubic root of 400009123 is about 736.8119012554.

Adding to 400009123 its reverse (321900004), we get a palindrome (721909127).

The spelling of 400009123 in words is "four hundred million, nine thousand, one hundred twenty-three".