1981871065 has 16 divisors (see below), whose sum is σ = 2422143360. Its totient is φ = 1556311680.

The previous prime is 1981871063. The next prime is 1981871069. The reversal of 1981871065 is 5601781891.

1981871065 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1981871065 - 2¹ = 1981871063 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1981871063) 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 15 ways as a sum of consecutive naturals, for example, 209845 + ... + 219085.

It is an arithmetic number, because the mean of its divisors is an integer number (151383960).

Almost surely, 2^1981871065 is an apocalyptic number.

It is an amenable number.

1981871065 is a deficient number, since it is larger than the sum of its proper divisors (440272295).

1981871065 is an equidigital number, since it uses as much as digits as its factorization.

1981871065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10032.

The product of its (nonzero) digits is 120960, while the sum is 46.

The square root of 1981871065 is about 44518.2104873949. The cubic root of 1981871065 is about 1256.1026514967.

The spelling of 1981871065 in words is "one billion, nine hundred eighty-one million, eight hundred seventy-one thousand, sixty-five".