394438172181 has 64 divisors (see below), whose sum is σ = 582761011200. Its totient is φ = 236194320384.

The previous prime is 394438172147. The next prime is 394438172189. The reversal of 394438172181 is 181271834493.

It is not a de Polignac number, because 394438172181 - 2¹⁸ = 394437910037 is a prime.

It is a super-2 number, since 2×394438172181² (a number of 24 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (394438172189) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 87398181 + ... + 87402693.

It is an arithmetic number, because the mean of its divisors is an integer number (9105640800).

Almost surely, 2^394438172181 is an apocalyptic number.

It is an amenable number.

394438172181 is a deficient number, since it is larger than the sum of its proper divisors (188322839019).

394438172181 is a wasteful number, since it uses less digits than its factorization.

394438172181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5130.

The product of its digits is 1161216, while the sum is 51.

The spelling of 394438172181 in words is "three hundred ninety-four billion, four hundred thirty-eight million, one hundred seventy-two thousand, one hundred eighty-one".