165605649 has 16 divisors (see below), whose sum is σ = 241182144. Its totient is φ = 100241600.

The previous prime is 165605639. The next prime is 165605663. The reversal of 165605649 is 946506561.

It is a cyclic number.

It is not a de Polignac number, because 165605649 - 2⁴ = 165605633 is a prime.

It is a super-2 number, since 2×165605649² = 54850461961422402, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 165605649.

It is not an unprimeable number, because it can be changed into a prime (165605639) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28387 + ... + 33719.

It is an arithmetic number, because the mean of its divisors is an integer number (15073884).

Almost surely, 2^165605649 is an apocalyptic number.

It is an amenable number.

165605649 is a deficient number, since it is larger than the sum of its proper divisors (75576495).

165605649 is a wasteful number, since it uses less digits than its factorization.

165605649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6288.

The product of its (nonzero) digits is 194400, while the sum is 42.

The square root of 165605649 is about 12868.7858401638. The cubic root of 165605649 is about 549.1509201839.

The spelling of 165605649 in words is "one hundred sixty-five million, six hundred five thousand, six hundred forty-nine".