1665981853 has 2 divisors, whose sum is σ = 1665981854. Its totient is φ = 1665981852.

The previous prime is 1665981851. The next prime is 1665981899. The reversal of 1665981853 is 3581895661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1661133049 + 4848804 = 40757^2 + 2202^2 .

It is a cyclic number.

It is not a de Polignac number, because 1665981853 - 2¹ = 1665981851 is a prime.

Together with 1665981851, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1665981853.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1665981851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832990926 + 832990927.

It is an arithmetic number, because the mean of its divisors is an integer number (832990927).

Almost surely, 2^1665981853 is an apocalyptic number.

It is an amenable number.

1665981853 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665981853 is an equidigital number, since it uses as much as digits as its factorization.

1665981853 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1555200, while the sum is 52.

The square root of 1665981853 is about 40816.4409643957. The cubic root of 1665981853 is about 1185.4686919742.

The spelling of 1665981853 in words is "one billion, six hundred sixty-five million, nine hundred eighty-one thousand, eight hundred fifty-three".