391781997441 has 12 divisors (see below), whose sum is σ = 568400316432. Its totient is φ = 260037389016.

The previous prime is 391781997403. The next prime is 391781997461. The reversal of 391781997441 is 144799187193.

391781997441 is a `hidden beast` number, since 3 + 9 + 178 + 19 + 9 + 7 + 441 = 666.

It is not a de Polignac number, because 391781997441 - 2³³ = 383192062849 is a prime.

It is not an unprimeable number, because it can be changed into a prime (391781997461) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 95881951 + ... + 95886036.

It is an arithmetic number, because the mean of its divisors is an integer number (47366693036).

Almost surely, 2^391781997441 is an apocalyptic number.

It is an amenable number.

391781997441 is a deficient number, since it is larger than the sum of its proper divisors (176618318991).

391781997441 is a wasteful number, since it uses less digits than its factorization.

391781997441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191768220 (or 191768217 counting only the distinct ones).

The product of its digits is 13716864, while the sum is 63.

The spelling of 391781997441 in words is "three hundred ninety-one billion, seven hundred eighty-one million, nine hundred ninety-seven thousand, four hundred forty-one".