8197420391 has 4 divisors (see below), whose sum is σ = 8197619400. Its totient is φ = 8197221384.

The previous prime is 8197420381. The next prime is 8197420393. The reversal of 8197420391 is 1930247918.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1930247918 = 2 ⋅965123959.

It is a cyclic number.

It is not a de Polignac number, because 8197420391 - 2¹⁰ = 8197419367 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8197420393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12161 + ... + 128618.

It is an arithmetic number, because the mean of its divisors is an integer number (2049404850).

Almost surely, 2^8197420391 is an apocalyptic number.

8197420391 is a deficient number, since it is larger than the sum of its proper divisors (199009).

8197420391 is a wasteful number, since it uses less digits than its factorization.

8197420391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199008.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 8197420391 is about 90539.6067530669. The cubic root of 8197420391 is about 2016.3181953940.

The spelling of 8197420391 in words is "eight billion, one hundred ninety-seven million, four hundred twenty thousand, three hundred ninety-one".