400243009 has 4 divisors (see below), whose sum is σ = 401008816. Its totient is φ = 399477204.

The previous prime is 400243001. The next prime is 400243027. The reversal of 400243009 is 900342004.

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 not a de Polignac number, because 400243009 - 2³ = 400243001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (400243001) 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, 382119 + ... + 383164.

It is an arithmetic number, because the mean of its divisors is an integer number (100252204).

Almost surely, 2^400243009 is an apocalyptic number.

It is an amenable number.

400243009 is a deficient number, since it is larger than the sum of its proper divisors (765807).

400243009 is an equidigital number, since it uses as much as digits as its factorization.

400243009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 765806.

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 400243009 is about 20006.0743025712. The cubic root of 400243009 is about 736.9554783241.

The spelling of 400243009 in words is "four hundred million, two hundred forty-three thousand, nine".