399666907 has 4 divisors (see below), whose sum is σ = 399721680. Its totient is φ = 399612136.

The previous prime is 399666887. The next prime is 399666913. The reversal of 399666907 is 709666993.

It is a happy number.

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 399666907 - 2⁷ = 399666779 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399666977) 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, 14383 + ... + 31720.

It is an arithmetic number, because the mean of its divisors is an integer number (99930420).

Almost surely, 2^399666907 is an apocalyptic number.

399666907 is a deficient number, since it is larger than the sum of its proper divisors (54773).

399666907 is an equidigital number, since it uses as much as digits as its factorization.

399666907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54772.

The product of its (nonzero) digits is 3306744, while the sum is 55.

The square root of 399666907 is about 19991.6709406693. The cubic root of 399666907 is about 736.6017220807.

The spelling of 399666907 in words is "three hundred ninety-nine million, six hundred sixty-six thousand, nine hundred seven".