1982111809 has 2 divisors, whose sum is σ = 1982111810. Its totient is φ = 1982111808.

The previous prime is 1982111801. The next prime is 1982111819. The reversal of 1982111809 is 9081112891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1673055409 + 309056400 = 40903^2 + 17580^2 .

It is an emirp because it is prime and its reverse (9081112891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1982111809 - 2³ = 1982111801 is a prime.

It is not a weakly prime, because it can be changed into another prime (1982111801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 991055904 + 991055905.

It is an arithmetic number, because the mean of its divisors is an integer number (991055905).

Almost surely, 2^1982111809 is an apocalyptic number.

It is an amenable number.

1982111809 is a deficient number, since it is larger than the sum of its proper divisors (1).

1982111809 is an equidigital number, since it uses as much as digits as its factorization.

1982111809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 40.

The square root of 1982111809 is about 44520.9142875570. The cubic root of 1982111809 is about 1256.1535103270.

The spelling of 1982111809 in words is "one billion, nine hundred eighty-two million, one hundred eleven thousand, eight hundred nine".