393885703681 has 4 divisors (see below), whose sum is σ = 397499334100. Its totient is φ = 390272073264.

The previous prime is 393885703661. The next prime is 393885703721. The reversal of 393885703681 is 186307588393.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 186307588393 = 19 ⋅9805662547.

It can be written as a sum of positive squares in 2 ways, for example, as 353531322225 + 40354381456 = 594585^2 + 200884^2 .

It is a cyclic number.

It is not a de Polignac number, because 393885703681 - 2⁷ = 393885703553 is a prime.

It is a super-2 number, since 2×393885703681² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (393885703661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1806815046 + ... + 1806815263.

It is an arithmetic number, because the mean of its divisors is an integer number (99374833525).

Almost surely, 2^393885703681 is an apocalyptic number.

It is an amenable number.

393885703681 is a deficient number, since it is larger than the sum of its proper divisors (3613630419).

393885703681 is a wasteful number, since it uses less digits than its factorization.

393885703681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3613630418.

The product of its (nonzero) digits is 26127360, while the sum is 61.

The spelling of 393885703681 in words is "three hundred ninety-three billion, eight hundred eighty-five million, seven hundred three thousand, six hundred eighty-one".