394037667665 has 4 divisors (see below), whose sum is σ = 472845201204. Its totient is φ = 315230134128.

The previous prime is 394037667659. The next prime is 394037667677. The reversal of 394037667665 is 566766730493.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 566766730493 = 749401 ⋅756293.

It can be written as a sum of positive squares in 2 ways, for example, as 62124565504 + 331913102161 = 249248^2 + 576119^2 .

It is a cyclic number.

It is not a de Polignac number, because 394037667665 - 2²⁰ = 394036619089 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 394037667598 and 394037667607.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39403766762 + ... + 39403766771.

It is an arithmetic number, because the mean of its divisors is an integer number (118211300301).

Almost surely, 2^394037667665 is an apocalyptic number.

It is an amenable number.

394037667665 is a deficient number, since it is larger than the sum of its proper divisors (78807533539).

394037667665 is an equidigital number, since it uses as much as digits as its factorization.

394037667665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78807533538.

The product of its (nonzero) digits is 102876480, while the sum is 62.

The spelling of 394037667665 in words is "three hundred ninety-four billion, thirty-seven million, six hundred sixty-seven thousand, six hundred sixty-five".