399575646 has 64 divisors (see below), whose sum is σ = 911347200. Its totient is φ = 129729600.

The previous prime is 399575621. The next prime is 399575653. The reversal of 399575646 is 646575993.

399575646 is a `hidden beast` number, since 3 + 9 + 9 + 575 + 64 + 6 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 399575592 and 399575601.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 340641 + ... + 341811.

It is an arithmetic number, because the mean of its divisors is an integer number (14239800).

Almost surely, 2^399575646 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399575646, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (455673600).

399575646 is an abundant number, since it is smaller than the sum of its proper divisors (511771554).

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

399575646 is a wasteful number, since it uses less digits than its factorization.

399575646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1342 (or 1336 counting only the distinct ones).

The product of its digits is 6123600, while the sum is 54.

The square root of 399575646 is about 19989.3883348140. The cubic root of 399575646 is about 736.5456519501.

The spelling of 399575646 in words is "three hundred ninety-nine million, five hundred seventy-five thousand, six hundred forty-six".