19861557987 has 8 divisors (see below), whose sum is σ = 26644544704. Its totient is φ = 13159804968.

The previous prime is 19861557973. The next prime is 19861558009. The reversal of 19861557987 is 78975516891.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 19861557987 - 2⁶ = 19861557923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19861507987) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20307853 + ... + 20308830.

It is an arithmetic number, because the mean of its divisors is an integer number (3330568088).

Almost surely, 2^19861557987 is an apocalyptic number.

19861557987 is a deficient number, since it is larger than the sum of its proper divisors (6782986717).

19861557987 is a wasteful number, since it uses less digits than its factorization.

19861557987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40616849.

The product of its digits is 38102400, while the sum is 66.

The spelling of 19861557987 in words is "nineteen billion, eight hundred sixty-one million, five hundred fifty-seven thousand, nine hundred eighty-seven".