399668386561 has 8 divisors (see below), whose sum is σ = 400217835200. Its totient is φ = 399119268240.

The previous prime is 399668386549. The next prime is 399668386567. The reversal of 399668386561 is 165683866993.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 399668386561 - 2¹¹ = 399668384513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399668386567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2389570 + ... + 2551348.

It is an arithmetic number, because the mean of its divisors is an integer number (50027229400).

Almost surely, 2^399668386561 is an apocalyptic number.

It is an amenable number.

399668386561 is a deficient number, since it is larger than the sum of its proper divisors (549448639).

399668386561 is a wasteful number, since it uses less digits than its factorization.

399668386561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165159.

The product of its digits is 302330880, while the sum is 70.

The spelling of 399668386561 in words is "three hundred ninety-nine billion, six hundred sixty-eight million, three hundred eighty-six thousand, five hundred sixty-one".