165953432509 has 2 divisors, whose sum is σ = 165953432510. Its totient is φ = 165953432508.

The previous prime is 165953432441. The next prime is 165953432531. The reversal of 165953432509 is 905234359561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 149882799609 + 16070632900 = 387147^2 + 126770^2 .

It is a cyclic number.

It is not a de Polignac number, because 165953432509 - 2³³ = 157363497917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165953432569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82976716254 + 82976716255.

It is an arithmetic number, because the mean of its divisors is an integer number (82976716255).

Almost surely, 2^165953432509 is an apocalyptic number.

It is an amenable number.

165953432509 is a deficient number, since it is larger than the sum of its proper divisors (1).

165953432509 is an equidigital number, since it uses as much as digits as its factorization.

165953432509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4374000, while the sum is 52.

The spelling of 165953432509 in words is "one hundred sixty-five billion, nine hundred fifty-three million, four hundred thirty-two thousand, five hundred nine".