199901387987 has 12 divisors (see below), whose sum is σ = 237485976480. Its totient is φ = 167698426896.

The previous prime is 199901387981. The next prime is 199901387989. The reversal of 199901387987 is 789783109991.

199901387987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 199901387987 - 2¹⁸ = 199901125843 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 199901387987.

It is not an unprimeable number, because it can be changed into a prime (199901387981) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 43397912 + ... + 43402517.

It is an arithmetic number, because the mean of its divisors is an integer number (19790498040).

Almost surely, 2^199901387987 is an apocalyptic number.

199901387987 is a deficient number, since it is larger than the sum of its proper divisors (37584588493).

199901387987 is an equidigital number, since it uses as much as digits as its factorization.

199901387987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86800490 (or 86800483 counting only the distinct ones).

The product of its (nonzero) digits is 61725888, while the sum is 71.

The spelling of 199901387987 in words is "one hundred ninety-nine billion, nine hundred one million, three hundred eighty-seven thousand, nine hundred eighty-seven".