400012409 has 4 divisors (see below), whose sum is σ = 400258404. Its totient is φ = 399766416.

The previous prime is 400012387. The next prime is 400012423. The reversal of 400012409 is 904210004.

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

It can be written as a sum of positive squares in 2 ways, for example, as 142730809 + 257281600 = 11947^2 + 16040^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-400012409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (400012489) 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, 120542 + ... + 123815.

It is an arithmetic number, because the mean of its divisors is an integer number (100064601).

Almost surely, 2^400012409 is an apocalyptic number.

It is an amenable number.

400012409 is a deficient number, since it is larger than the sum of its proper divisors (245995).

400012409 is a wasteful number, since it uses less digits than its factorization.

400012409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245994.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 400012409 is about 20000.3102225940. The cubic root of 400012409 is about 736.8139188404.

The spelling of 400012409 in words is "four hundred million, twelve thousand, four hundred nine".