399423904 has 72 divisors (see below), whose sum is σ = 884822400. Its totient is φ = 177260160.

The previous prime is 399423887. The next prime is 399423943. The reversal of 399423904 is 409324993.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 165297 + ... + 167695.

It is an arithmetic number, because the mean of its divisors is an integer number (12289200).

Almost surely, 2^399423904 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399423904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (442411200).

399423904 is an abundant number, since it is smaller than the sum of its proper divisors (485398496).

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

399423904 is a wasteful number, since it uses less digits than its factorization.

399423904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2474 (or 2455 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 43.

The square root of 399423904 is about 19985.5924105341. The cubic root of 399423904 is about 736.4524038069.

The spelling of 399423904 in words is "three hundred ninety-nine million, four hundred twenty-three thousand, nine hundred four".