399579997 has 2 divisors, whose sum is σ = 399579998. Its totient is φ = 399579996.

The previous prime is 399579991. The next prime is 399580031. The reversal of 399579997 is 799975993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 375235641 + 24344356 = 19371^2 + 4934^2 .

It is an emirp because it is prime and its reverse (799975993) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 399579997 - 2¹¹ = 399577949 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (399579991) 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 as a sum of consecutive naturals, namely, 199789998 + 199789999.

It is an arithmetic number, because the mean of its divisors is an integer number (199789999).

Almost surely, 2^399579997 is an apocalyptic number.

It is an amenable number.

399579997 is a deficient number, since it is larger than the sum of its proper divisors (1).

399579997 is an equidigital number, since it uses as much as digits as its factorization.

399579997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43401015, while the sum is 67.

The square root of 399579997 is about 19989.4971672626. The cubic root of 399579997 is about 736.5483253684.

The spelling of 399579997 in words is "three hundred ninety-nine million, five hundred seventy-nine thousand, nine hundred ninety-seven".