399038640 has 480 divisors, whose sum is σ = 1684558848. Its totient is φ = 76032000.

The previous prime is 399038617. The next prime is 399038641. The reversal of 399038640 is 46830993.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 399038592 and 399038601.

It is not an unprimeable number, because it can be changed into a prime (399038641) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2642565 + ... + 2642715.

Almost surely, 2^399038640 is an apocalyptic number.

399038640 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399038640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (842279424).

399038640 is an abundant number, since it is smaller than the sum of its proper divisors (1285520208).

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

399038640 is a wasteful number, since it uses less digits than its factorization.

399038640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209 (or 192 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 42.

The square root of 399038640 is about 19975.9515417914. The cubic root of 399038640 is about 736.2155461157.

The spelling of 399038640 in words is "three hundred ninety-nine million, thirty-eight thousand, six hundred forty".