399179915 has 4 divisors (see below), whose sum is σ = 479015904. Its totient is φ = 319343928.

The previous prime is 399179887. The next prime is 399179947. The reversal of 399179915 is 519971993.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 519971993 = 19 ⋅27366947.

It is a cyclic number.

It is not a de Polignac number, because 399179915 - 2⁸ = 399179659 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39917987 + ... + 39917996.

It is an arithmetic number, because the mean of its divisors is an integer number (119753976).

Almost surely, 2^399179915 is an apocalyptic number.

399179915 is a deficient number, since it is larger than the sum of its proper divisors (79835989).

399179915 is an equidigital number, since it uses as much as digits as its factorization.

399179915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79835988.

The product of its digits is 688905, while the sum is 53.

The square root of 399179915 is about 19979.4873557857. The cubic root of 399179915 is about 736.3024187214.

The spelling of 399179915 in words is "three hundred ninety-nine million, one hundred seventy-nine thousand, nine hundred fifteen".