399385836 has 48 divisors (see below), whose sum is σ = 1040704000. Its totient is φ = 132452496.

The previous prime is 399385813. The next prime is 399385859. The reversal of 399385836 is 638583993.

It is an interprime number because it is at equal distance from previous prime (399385813) and next prime (399385859).

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12201 + ... + 30783.

Almost surely, 2^399385836 is an apocalyptic number.

399385836 is a gapful number since it is divisible by the number (36) 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 399385836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (520352000).

399385836 is an abundant number, since it is smaller than the sum of its proper divisors (641318164).

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

399385836 is a wasteful number, since it uses less digits than its factorization.

399385836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18795 (or 18787 counting only the distinct ones).

The product of its digits is 4199040, while the sum is 54.

The square root of 399385836 is about 19984.6400017614. The cubic root of 399385836 is about 736.4290066421.

The spelling of 399385836 in words is "three hundred ninety-nine million, three hundred eighty-five thousand, eight hundred thirty-six".