394161807781 has 16 divisors (see below), whose sum is σ = 476992938240. Its totient is φ = 317963255040.

The previous prime is 394161807779. The next prime is 394161807847. The reversal of 394161807781 is 187708161493.

It is a cyclic number.

It is not a de Polignac number, because 394161807781 - 2¹ = 394161807779 is a prime.

It is a super-2 number, since 2×394161807781² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (394161807731) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2668536 + ... + 2812366.

It is an arithmetic number, because the mean of its divisors is an integer number (29812058640).

Almost surely, 2^394161807781 is an apocalyptic number.

It is an amenable number.

394161807781 is a deficient number, since it is larger than the sum of its proper divisors (82831130459).

394161807781 is a wasteful number, since it uses less digits than its factorization.

394161807781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166884.

The product of its (nonzero) digits is 2032128, while the sum is 55.

The spelling of 394161807781 in words is "three hundred ninety-four billion, one hundred sixty-one million, eight hundred seven thousand, seven hundred eighty-one".