19887685847 has 2 divisors, whose sum is σ = 19887685848. Its totient is φ = 19887685846.

The previous prime is 19887685771. The next prime is 19887685849. The reversal of 19887685847 is 74858678891.

It is a strong prime.

It is an emirp because it is prime and its reverse (74858678891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19887685847 - 2¹⁰ = 19887684823 is a prime.

Together with 19887685849, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19887685849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9943842923 + 9943842924.

It is an arithmetic number, because the mean of its divisors is an integer number (9943842924).

Almost surely, 2^19887685847 is an apocalyptic number.

19887685847 is a deficient number, since it is larger than the sum of its proper divisors (1).

19887685847 is an equidigital number, since it uses as much as digits as its factorization.

19887685847 is an evil number, because the sum of its binary digits is even.

The product of its digits is 216760320, while the sum is 71.

The spelling of 19887685847 in words is "nineteen billion, eight hundred eighty-seven million, six hundred eighty-five thousand, eight hundred forty-seven".