165945563 has 24 divisors (see below), whose sum is σ = 202521312. Its totient is φ = 133166592.

The previous prime is 165945553. The next prime is 165945581. The reversal of 165945563 is 365549561.

It is not a de Polignac number, because 165945563 - 2⁴ = 165945547 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165945553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 244781 + ... + 245457.

It is an arithmetic number, because the mean of its divisors is an integer number (8438388).

Almost surely, 2^165945563 is an apocalyptic number.

165945563 is a deficient number, since it is larger than the sum of its proper divisors (36575749).

165945563 is an equidigital number, since it uses as much as digits as its factorization.

165945563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 819 (or 800 counting only the distinct ones).

The product of its digits is 486000, while the sum is 44.

The square root of 165945563 is about 12881.9859881930. The cubic root of 165945563 is about 549.5263834605.

The spelling of 165945563 in words is "one hundred sixty-five million, nine hundred forty-five thousand, five hundred sixty-three".