19887287138 has 8 divisors (see below), whose sum is σ = 30859583580. Its totient is φ = 9600759280.

The previous prime is 19887287129. The next prime is 19887287153. The reversal of 19887287138 is 83178278891.

It can be written as a sum of positive squares in 2 ways, for example, as 17435353849 + 2451933289 = 132043^2 + 49517^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 171442073 + ... + 171442188.

Almost surely, 2^19887287138 is an apocalyptic number.

19887287138 is a deficient number, since it is larger than the sum of its proper divisors (10972296442).

19887287138 is a wasteful number, since it uses less digits than its factorization.

19887287138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342884292.

The product of its digits is 10838016, while the sum is 62.

The spelling of 19887287138 in words is "nineteen billion, eight hundred eighty-seven million, two hundred eighty-seven thousand, one hundred thirty-eight".