199781988 has 24 divisors (see below), whose sum is σ = 532752192. Its totient is φ = 57080544.

The previous prime is 199781987. The next prime is 199782047. The reversal of 199781988 is 889187991.

It is not an unprimeable number, because it can be changed into a prime (199781987) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1189095 + ... + 1189262.

It is an arithmetic number, because the mean of its divisors is an integer number (22198008).

Almost surely, 2^199781988 is an apocalyptic number.

It is an amenable number.

199781988 is an abundant number, since it is smaller than the sum of its proper divisors (332970204).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

199781988 is a wasteful number, since it uses less digits than its factorization.

199781988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2378371 (or 2378369 counting only the distinct ones).

The product of its digits is 2612736, while the sum is 60.

The square root of 199781988 is about 14134.4256338912. The cubic root of 199781988 is about 584.5909800683.

The spelling of 199781988 in words is "one hundred ninety-nine million, seven hundred eighty-one thousand, nine hundred eighty-eight".