1990365565 has 4 divisors (see below), whose sum is σ = 2388438684. Its totient is φ = 1592292448.

The previous prime is 1990365547. The next prime is 1990365617. The reversal of 1990365565 is 5655630991.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5655630991 = 19 ⋅297664789.

It can be written as a sum of positive squares in 2 ways, for example, as 725709721 + 1264655844 = 26939^2 + 35562^2 .

It is a cyclic number.

It is not a de Polignac number, because 1990365565 - 2¹³ = 1990357373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 199036552 + ... + 199036561.

It is an arithmetic number, because the mean of its divisors is an integer number (597109671).

Almost surely, 2^1990365565 is an apocalyptic number.

It is an amenable number.

1990365565 is a deficient number, since it is larger than the sum of its proper divisors (398073119).

1990365565 is an equidigital number, since it uses as much as digits as its factorization.

1990365565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398073118.

The product of its (nonzero) digits is 1093500, while the sum is 49.

The square root of 1990365565 is about 44613.5132555149. The cubic root of 1990365565 is about 1257.8946880179.

The spelling of 1990365565 in words is "one billion, nine hundred ninety million, three hundred sixty-five thousand, five hundred sixty-five".