19791718481 has 18 divisors (see below), whose sum is σ = 20554147782. Its totient is φ = 19046220480.

The previous prime is 19791718459. The next prime is 19791718493. The reversal of 19791718481 is 18481719791.

It can be written as a sum of positive squares in 3 ways, for example, as 6140132881 + 13651585600 = 78359^2 + 116840^2 .

It is not a de Polignac number, because 19791718481 - 2¹⁸ = 19791456337 is a prime.

It is a super-2 number, since 2×19791718481² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19791718781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 114402911 + ... + 114403083.

It is an arithmetic number, because the mean of its divisors is an integer number (1141897099).

Almost surely, 2^19791718481 is an apocalyptic number.

It is an amenable number.

19791718481 is a deficient number, since it is larger than the sum of its proper divisors (762429301).

19791718481 is an frugal number, since it uses more digits than its factorization.

19791718481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 641 (or 341 counting only the distinct ones).

The product of its digits is 1016064, while the sum is 56.

The spelling of 19791718481 in words is "nineteen billion, seven hundred ninety-one million, seven hundred eighteen thousand, four hundred eighty-one".