394407910661 has 4 divisors (see below), whose sum is σ = 417608376012. Its totient is φ = 371207445312.

The previous prime is 394407910601. The next prime is 394407910679. The reversal of 394407910661 is 166019704493.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166019704493 = 4783 ⋅34710371.

It can be written as a sum of positive squares in 2 ways, for example, as 297767753761 + 96640156900 = 545681^2 + 310870^2 .

It is a cyclic number.

It is not a de Polignac number, because 394407910661 - 2²⁶ = 394340801797 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (394407910601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11600232650 + ... + 11600232683.

It is an arithmetic number, because the mean of its divisors is an integer number (104402094003).

Almost surely, 2^394407910661 is an apocalyptic number.

It is an amenable number.

394407910661 is a deficient number, since it is larger than the sum of its proper divisors (23200465351).

394407910661 is a wasteful number, since it uses less digits than its factorization.

394407910661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23200465350.

The product of its (nonzero) digits is 979776, while the sum is 50.

The spelling of 394407910661 in words is "three hundred ninety-four billion, four hundred seven million, nine hundred ten thousand, six hundred sixty-one".