399203609 has 4 divisors (see below), whose sum is σ = 456232704. Its totient is φ = 342174516.

The previous prime is 399203603. The next prime is 399203641. The reversal of 399203609 is 906302993.

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 not a de Polignac number, because 399203609 - 2²⁸ = 130768153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399203603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28514537 + ... + 28514550.

It is an arithmetic number, because the mean of its divisors is an integer number (114058176).

Almost surely, 2^399203609 is an apocalyptic number.

It is an amenable number.

399203609 is a deficient number, since it is larger than the sum of its proper divisors (57029095).

399203609 is an equidigital number, since it uses as much as digits as its factorization.

399203609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57029094.

The product of its (nonzero) digits is 78732, while the sum is 41.

The square root of 399203609 is about 19980.0803051439. The cubic root of 399203609 is about 736.3169865922.

The spelling of 399203609 in words is "three hundred ninety-nine million, two hundred three thousand, six hundred nine".