1990043985 has 16 divisors (see below), whose sum is σ = 3187806336. Its totient is φ = 1060111488.

The previous prime is 1990043969. The next prime is 1990043989. The reversal of 1990043985 is 5893400991.

It is not a de Polignac number, because 1990043985 - 2⁴ = 1990043969 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1990043989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64549 + ... + 90258.

It is an arithmetic number, because the mean of its divisors is an integer number (199237896).

Almost surely, 2^1990043985 is an apocalyptic number.

1990043985 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1990043985 is a deficient number, since it is larger than the sum of its proper divisors (1197762351).

1990043985 is a wasteful number, since it uses less digits than its factorization.

1990043985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155672.

The product of its (nonzero) digits is 349920, while the sum is 48.

The square root of 1990043985 is about 44609.9090449644. The cubic root of 1990043985 is about 1257.8269390629.

The spelling of 1990043985 in words is "one billion, nine hundred ninety million, forty-three thousand, nine hundred eighty-five".