199987840 has 144 divisors (see below), whose sum is σ = 530021070. Its totient is φ = 72124416.

The previous prime is 199987811. The next prime is 199987841. The reversal of 199987840 is 48789991.

It can be written as a sum of positive squares in 3 ways, for example, as 86266944 + 113720896 = 9288^2 + 10664^2 .

It is a super-2 number, since 2×199987840² = 79990272295731200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (199987841) 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 17 ways as a sum of consecutive naturals, for example, 4650859 + ... + 4650901.

Almost surely, 2^199987840 is an apocalyptic number.

199987840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 199987840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (265010535).

199987840 is an abundant number, since it is smaller than the sum of its proper divisors (330033230).

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

199987840 is an equidigital number, since it uses as much as digits as its factorization.

199987840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131 (or 63 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 55.

The square root of 199987840 is about 14141.7056962730. The cubic root of 199987840 is about 584.7916953838.

The spelling of 199987840 in words is "one hundred ninety-nine million, nine hundred eighty-seven thousand, eight hundred forty".