399505878 has 32 divisors (see below), whose sum is σ = 888451200. Its totient is φ = 133069608.

The previous prime is 399505871. The next prime is 399505889. The reversal of 399505878 is 878505993.

399505878 is a `hidden beast` number, since 3 + 9 + 9 + 50 + 587 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399505871) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 124725 + ... + 127887.

It is an arithmetic number, because the mean of its divisors is an integer number (27764100).

Almost surely, 2^399505878 is an apocalyptic number.

399505878 is an abundant number, since it is smaller than the sum of its proper divisors (488945322).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

399505878 is a wasteful number, since it uses less digits than its factorization.

399505878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5513 (or 5507 counting only the distinct ones).

The product of its (nonzero) digits is 2721600, while the sum is 54.

The square root of 399505878 is about 19987.6431326958. The cubic root of 399505878 is about 736.5027812124.

The spelling of 399505878 in words is "three hundred ninety-nine million, five hundred five thousand, eight hundred seventy-eight".