19887708523 has 4 divisors (see below), whose sum is σ = 19891660320. Its totient is φ = 19883756728.

The previous prime is 19887708487. The next prime is 19887708527. The reversal of 19887708523 is 32580778891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32580778891 = 3527 ⋅9237533.

It is a cyclic number.

It is not a de Polignac number, because 19887708523 - 2¹³ = 19887700331 is a prime.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19887708527) 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, 1968340 + ... + 1978417.

It is an arithmetic number, because the mean of its divisors is an integer number (4972915080).

Almost surely, 2^19887708523 is an apocalyptic number.

19887708523 is a deficient number, since it is larger than the sum of its proper divisors (3951797).

19887708523 is an equidigital number, since it uses as much as digits as its factorization.

19887708523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3951796.

The product of its (nonzero) digits is 6773760, while the sum is 58.

The spelling of 19887708523 in words is "nineteen billion, eight hundred eighty-seven million, seven hundred eight thousand, five hundred twenty-three".