399889815 has 16 divisors (see below), whose sum is σ = 689041248. Its totient is φ = 196868736.

The previous prime is 399889757. The next prime is 399889849. The reversal of 399889815 is 518988993.

It is not a de Polignac number, because 399889815 - 2⁸ = 399889559 is a prime.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 1025164 + ... + 1025553.

It is an arithmetic number, because the mean of its divisors is an integer number (43065078).

Almost surely, 2^399889815 is an apocalyptic number.

399889815 is a deficient number, since it is larger than the sum of its proper divisors (289151433).

399889815 is a wasteful number, since it uses less digits than its factorization.

399889815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2050738.

The product of its digits is 5598720, while the sum is 60.

The square root of 399889815 is about 19997.2451852749. The cubic root of 399889815 is about 736.7386393466.

The spelling of 399889815 in words is "three hundred ninety-nine million, eight hundred eighty-nine thousand, eight hundred fifteen".