165645481 has 4 divisors (see below), whose sum is σ = 166058964. Its totient is φ = 165232000.

The previous prime is 165645461. The next prime is 165645533. The reversal of 165645481 is 184546561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 162333081 + 3312400 = 12741^2 + 1820^2 .

It is a cyclic number.

It is not a de Polignac number, because 165645481 - 2¹⁹ = 165121193 is a prime.

It is a super-2 number, since 2×165645481² = 54876850751442722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165645421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 206140 + ... + 206941.

It is an arithmetic number, because the mean of its divisors is an integer number (41514741).

Almost surely, 2^165645481 is an apocalyptic number.

It is an amenable number.

165645481 is a deficient number, since it is larger than the sum of its proper divisors (413483).

165645481 is an equidigital number, since it uses as much as digits as its factorization.

165645481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 413482.

The product of its digits is 115200, while the sum is 40.

The square root of 165645481 is about 12870.3333678658. Note that the first 4 decimals coincide. The cubic root of 165645481 is about 549.1949444993.

The spelling of 165645481 in words is "one hundred sixty-five million, six hundred forty-five thousand, four hundred eighty-one".