1665065639 has 2 divisors, whose sum is σ = 1665065640. Its totient is φ = 1665065638.

The previous prime is 1665065621. The next prime is 1665065669. The reversal of 1665065639 is 9365605661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1665065639 - 2²⁰ = 1664017063 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1665065593 and 1665065602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1665065669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832532819 + 832532820.

It is an arithmetic number, because the mean of its divisors is an integer number (832532820).

Almost surely, 2^1665065639 is an apocalyptic number.

1665065639 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665065639 is an equidigital number, since it uses as much as digits as its factorization.

1665065639 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 874800, while the sum is 47.

The square root of 1665065639 is about 40805.2158308224. The cubic root of 1665065639 is about 1185.2513342279.

The spelling of 1665065639 in words is "one billion, six hundred sixty-five million, sixty-five thousand, six hundred thirty-nine".