1990659889 has 4 divisors (see below), whose sum is σ = 1990753380. Its totient is φ = 1990566400.

The previous prime is 1990659883. The next prime is 1990659893. The reversal of 1990659889 is 9889560991.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 9889560991 = 5483 ⋅1803677.

It can be written as a sum of positive squares in 2 ways, for example, as 738915489 + 1251744400 = 27183^2 + 35380^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1990659889 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 1990659889.

It is not an unprimeable number, because it can be changed into a prime (1990659883) 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 3 ways as a sum of consecutive naturals, for example, 2457 + ... + 63145.

It is an arithmetic number, because the mean of its divisors is an integer number (497688345).

Almost surely, 2^1990659889 is an apocalyptic number.

It is an amenable number.

1990659889 is a deficient number, since it is larger than the sum of its proper divisors (93491).

1990659889 is an equidigital number, since it uses as much as digits as its factorization.

1990659889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93490.

The product of its (nonzero) digits is 12597120, while the sum is 64.

The square root of 1990659889 is about 44616.8117305574. The cubic root of 1990659889 is about 1257.9566884121.

The spelling of 1990659889 in words is "one billion, nine hundred ninety million, six hundred fifty-nine thousand, eight hundred eighty-nine".