399511978 has 8 divisors (see below), whose sum is σ = 625323168. Its totient is φ = 191070924.

The previous prime is 399511969. The next prime is 399512021. The reversal of 399511978 is 879115993.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

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, 4342476 + ... + 4342567.

It is an arithmetic number, because the mean of its divisors is an integer number (78165396).

Almost surely, 2^399511978 is an apocalyptic number.

399511978 is a deficient number, since it is larger than the sum of its proper divisors (225811190).

399511978 is a wasteful number, since it uses less digits than its factorization.

399511978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8685068.

The product of its digits is 612360, while the sum is 52.

The square root of 399511978 is about 19987.7957263926. The cubic root of 399511978 is about 736.5065297130.

The spelling of 399511978 in words is "three hundred ninety-nine million, five hundred eleven thousand, nine hundred seventy-eight".