399165408 has 168 divisors, whose sum is σ = 1199799216. Its totient is φ = 130636800.

The previous prime is 399165397. The next prime is 399165409. The reversal of 399165408 is 804561993.

It is a happy number.

399165408 is a `hidden beast` number, since 3 + 99 + 16 + 540 + 8 = 666.

It is a super-3 number, since 3×399165408³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399165409) 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, 1656168 + ... + 1656408.

It is an arithmetic number, because the mean of its divisors is an integer number (7141662).

Almost surely, 2^399165408 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 399165408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (599899608).

399165408 is an abundant number, since it is smaller than the sum of its proper divisors (800633808).

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

399165408 is an equidigital number, since it uses as much as digits as its factorization.

399165408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340 (or 317 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The square root of 399165408 is about 19979.1243051341. The cubic root of 399165408 is about 736.2934990437.

The spelling of 399165408 in words is "three hundred ninety-nine million, one hundred sixty-five thousand, four hundred eight".