1990899616609 has 2 divisors, whose sum is σ = 1990899616610. Its totient is φ = 1990899616608.

The previous prime is 1990899616603. The next prime is 1990899616619. The reversal of 1990899616609 is 9066169980991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1912066700625 + 78832915984 = 1382775^2 + 280772^2 .

It is a cyclic number.

It is not a de Polignac number, because 1990899616609 - 2⁷ = 1990899616481 is a prime.

It is not a weakly prime, because it can be changed into another prime (1990899616603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995449808304 + 995449808305.

It is an arithmetic number, because the mean of its divisors is an integer number (995449808305).

Almost surely, 2^{1990899616609} is an apocalyptic number.

It is an amenable number.

1990899616609 is a deficient number, since it is larger than the sum of its proper divisors (1).

1990899616609 is an equidigital number, since it uses as much as digits as its factorization.

1990899616609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 102036672, while the sum is 73.

The spelling of 1990899616609 in words is "one trillion, nine hundred ninety billion, eight hundred ninety-nine million, six hundred sixteen thousand, six hundred nine".