1865980809 has 135 divisors (see below), whose sum is σ = 3663678135. Its totient is φ = 912320640.

The previous prime is 1865980771. The next prime is 1865980847. The reversal of 1865980809 is 9080895681.

The square root of 1865980809 is 43197.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (1865980771) and next prime (1865980847).

It can be written as a sum of positive squares in only one way, i.e., 1452753225 + 413227584 = 38115^2 + 20328^2 .

It is not a de Polignac number, because 1865980809 - 2⁷ = 1865980681 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1865980849) 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 134 ways as a sum of consecutive naturals, for example, 109763569 + ... + 109763585.

Almost surely, 2^1865980809 is an apocalyptic number.

1865980809 is the 43197-th square number.

1865980809 is the 21599-th centered octagonal number.

It is an amenable number.

1865980809 is a deficient number, since it is larger than the sum of its proper divisors (1797697326).

1865980809 is an equidigital number, since it uses as much as digits as its factorization.

1865980809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98 (or 38 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 54.

The cubic root of 1865980809 is about 1231.1256817493.

The spelling of 1865980809 in words is "one billion, eight hundred sixty-five million, nine hundred eighty thousand, eight hundred nine".