394538781 has 48 divisors (see below), whose sum is σ = 685386240. Its totient is φ = 197121600.

The previous prime is 394538779. The next prime is 394538791. The reversal of 394538781 is 187835493.

It is not a de Polignac number, because 394538781 - 2¹ = 394538779 is a prime.

It is a super-3 number, since 3×394538781³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 394538781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (394538761) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 64506 + ... + 70356.

It is an arithmetic number, because the mean of its divisors is an integer number (14278880).

Almost surely, 2^394538781 is an apocalyptic number.

It is an amenable number.

394538781 is a deficient number, since it is larger than the sum of its proper divisors (290847459).

394538781 is a wasteful number, since it uses less digits than its factorization.

394538781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5906 (or 5893 counting only the distinct ones).

The product of its digits is 725760, while the sum is 48.

The square root of 394538781 is about 19863.0003020692. Note that the first 3 decimals coincide. The cubic root of 394538781 is about 733.4377052318.

The spelling of 394538781 in words is "three hundred ninety-four million, five hundred thirty-eight thousand, seven hundred eighty-one".