19861237897 has 4 divisors (see below), whose sum is σ = 19861843716. Its totient is φ = 19860632080.

The previous prime is 19861237873. The next prime is 19861237901. The reversal of 19861237897 is 79873216891.

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 8062064521 + 11799173376 = 89789^2 + 108624^2 .

It is a cyclic number.

It is not a de Polignac number, because 19861237897 - 2¹⁵ = 19861205129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19861237867) 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 3 ways as a sum of consecutive naturals, for example, 250738 + ... + 320299.

It is an arithmetic number, because the mean of its divisors is an integer number (4965460929).

Almost surely, 2^19861237897 is an apocalyptic number.

It is an amenable number.

19861237897 is a deficient number, since it is larger than the sum of its proper divisors (605819).

19861237897 is an equidigital number, since it uses as much as digits as its factorization.

19861237897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 605818.

The product of its digits is 9144576, while the sum is 61.

The spelling of 19861237897 in words is "nineteen billion, eight hundred sixty-one million, two hundred thirty-seven thousand, eight hundred ninety-seven".