391192421881 has 4 divisors (see below), whose sum is σ = 391193856612. Its totient is φ = 391190987152.

The previous prime is 391192421863. The next prime is 391192421909. The reversal of 391192421881 is 188124291193.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 233376914281 + 157815507600 = 483091^2 + 397260^2 .

It is a cyclic number.

It is not a de Polignac number, because 391192421881 - 2⁹ = 391192421369 is a prime.

It is a super-2 number, since 2×391192421881² (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 (395192421881) 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, 168286 + ... + 900391.

It is an arithmetic number, because the mean of its divisors is an integer number (97798464153).

Almost surely, 2^391192421881 is an apocalyptic number.

It is an amenable number.

391192421881 is a deficient number, since it is larger than the sum of its proper divisors (1434731).

391192421881 is a wasteful number, since it uses less digits than its factorization.

391192421881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1434730.

The product of its digits is 248832, while the sum is 49.

The spelling of 391192421881 in words is "three hundred ninety-one billion, one hundred ninety-two million, four hundred twenty-one thousand, eight hundred eighty-one".