399631968 has 168 divisors, whose sum is σ = 1214121888. Its totient is φ = 129330432.

The previous prime is 399631963. The next prime is 399631987. The reversal of 399631968 is 869136993.

399631968 is a `hidden beast` number, since 399 + 63 + 196 + 8 = 666.

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399631963) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 862905 + ... + 863367.

It is an arithmetic number, because the mean of its divisors is an integer number (7226916).

Almost surely, 2^399631968 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 399631968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (607060944).

399631968 is an abundant number, since it is smaller than the sum of its proper divisors (814489920).

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

399631968 is an equidigital number, since it uses as much as digits as its factorization.

399631968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 528 (or 505 counting only the distinct ones).

The product of its digits is 1889568, while the sum is 54.

The square root of 399631968 is about 19990.7970826578. The cubic root of 399631968 is about 736.5802568080.

The spelling of 399631968 in words is "three hundred ninety-nine million, six hundred thirty-one thousand, nine hundred sixty-eight".