165640101 has 16 divisors (see below), whose sum is σ = 243321408. Its totient is φ = 99392000.

The previous prime is 165640091. The next prime is 165640117. The reversal of 165640101 is 101046561.

It is a cyclic number.

It is not a de Polignac number, because 165640101 - 2⁹ = 165639589 is a prime.

It is a super-3 number, since 3×165640101³ (a number of 26 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165640151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21516 + ... + 28181.

It is an arithmetic number, because the mean of its divisors is an integer number (15207588).

Almost surely, 2^165640101 is an apocalyptic number.

165640101 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165640101 is a deficient number, since it is larger than the sum of its proper divisors (77681307).

165640101 is a wasteful number, since it uses less digits than its factorization.

165640101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49812.

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 165640101 is about 12870.1243583735. The cubic root of 165640101 is about 549.1889986669.

Adding to 165640101 its reverse (101046561), we get a palindrome (266686662).

The spelling of 165640101 in words is "one hundred sixty-five million, six hundred forty thousand, one hundred one".