165638005 has 8 divisors (see below), whose sum is σ = 214055352. Its totient is φ = 122317248.

The previous prime is 165637993. The next prime is 165638009. The reversal of 165638005 is 500836561.

It can be written as a sum of positive squares in 4 ways, for example, as 15256836 + 150381169 = 3906^2 + 12263^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 165638005 - 2¹⁷ = 165506933 is a prime.

It is a super-3 number, since 3×165638005³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165638009) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1274074 + ... + 1274203.

It is an arithmetic number, because the mean of its divisors is an integer number (26756919).

Almost surely, 2^165638005 is an apocalyptic number.

It is an amenable number.

165638005 is a deficient number, since it is larger than the sum of its proper divisors (48417347).

165638005 is a wasteful number, since it uses less digits than its factorization.

165638005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2548295.

The product of its (nonzero) digits is 21600, while the sum is 34.

The square root of 165638005 is about 12870.0429292213. The cubic root of 165638005 is about 549.1866821888.

The spelling of 165638005 in words is "one hundred sixty-five million, six hundred thirty-eight thousand, five".