19887685845 has 8 divisors (see below), whose sum is σ = 31820297376. Its totient is φ = 10606765776.

The previous prime is 19887685771. The next prime is 19887685847. The reversal of 19887685845 is 54858678891.

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

It is not a de Polignac number, because 19887685845 - 2¹⁷ = 19887554773 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19887685845.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19887685847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 662922847 + ... + 662922876.

It is an arithmetic number, because the mean of its divisors is an integer number (3977537172).

Almost surely, 2^19887685845 is an apocalyptic number.

19887685845 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19887685845 is a deficient number, since it is larger than the sum of its proper divisors (11932611531).

19887685845 is a wasteful number, since it uses less digits than its factorization.

19887685845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1325845731.

The product of its digits is 154828800, while the sum is 69.

The spelling of 19887685845 in words is "nineteen billion, eight hundred eighty-seven million, six hundred eighty-five thousand, eight hundred forty-five".