399781824639066 has 48 divisors (see below), whose sum is σ = 911817102081600. Its totient is φ = 126242185233024.

The previous prime is 399781824639049. The next prime is 399781824639079. The reversal of 399781824639066 is 660936428187993.

399781824639066 is a `hidden beast` number, since 3 + 9 + 9 + 7 + 8 + 1 + 8 + 2 + 463 + 90 + 66 = 666.

It is a Smith number, since the sum of its digits (81) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12598191 + ... + 30956066.

It is an arithmetic number, because the mean of its divisors is an integer number (18996189626700).

Almost surely, 2^{399781824639066} is an apocalyptic number.

399781824639066 is an abundant number, since it is smaller than the sum of its proper divisors (512035277442534).

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

399781824639066 is a wasteful number, since it uses less digits than its factorization.

399781824639066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43581123 (or 43581120 counting only the distinct ones).

The product of its (nonzero) digits is 5079158784, while the sum is 81.

The spelling of 399781824639066 in words is "three hundred ninety-nine trillion, seven hundred eighty-one billion, eight hundred twenty-four million, six hundred thirty-nine thousand, sixty-six".