399920004 has 135 divisors (see below), whose sum is σ = 1160643253. Its totient is φ = 119988000.

The previous prime is 399919981. The next prime is 399920009. The reversal of 399920004 is 400029993.

The square root of 399920004 is 19998.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 384238404 + 15681600 = 19602^2 + 3960^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (399920009) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 3959554 + ... + 3959654.

Almost surely, 2^399920004 is an apocalyptic number.

399920004 is the 19998-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399920004

399920004 is an abundant number, since it is smaller than the sum of its proper divisors (760723249).

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

399920004 is a wasteful number, since it uses less digits than its factorization.

399920004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240 (or 117 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 36.

The cubic root of 399920004 is about 736.7571784894.

Multiplying 399920004 by its sum of digits (36), we get a square (14397120144 = 119988²).

399920004 divided by its sum of digits (36) gives a square (11108889 = 3333²).

Adding to 399920004 its reverse (400029993), we get a palindrome (799949997).

The spelling of 399920004 in words is "three hundred ninety-nine million, nine hundred twenty thousand, four".