1990805000 has 60 divisors (see below), whose sum is σ = 4671859995. Its totient is φ = 795060000.

The previous prime is 1990804999. The next prime is 1990805039. The reversal of 1990805000 is 5080991.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 3 ways, for example, as 460274116 + 1530530884 = 21454^2 + 39122^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=31550.

It is an unprimeable number.

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 14 ways as a sum of consecutive naturals, for example, 3154685 + ... + 3155315.

Almost surely, 2^1990805000 is an apocalyptic number.

1990805000 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 1990805000

1990805000 is an abundant number, since it is smaller than the sum of its proper divisors (2681054995).

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

1990805000 is an frugal number, since it uses more digits than its factorization.

1990805000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1288 (or 638 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 32.

The square root of 1990805000 is about 44618.4378928711. The cubic root of 1990805000 is about 1257.9872543094.

Multiplying 1990805000 by its sum of digits (32), we get a square (63705760000 = 252400²).

Adding to 1990805000 its reverse (5080991), we get a palindrome (1995885991).

The spelling of 1990805000 in words is "one billion, nine hundred ninety million, eight hundred five thousand".