165603212181 has 20 divisors (see below), whose sum is σ = 269871902784. Its totient is φ = 100365582600.

The previous prime is 165603212179. The next prime is 165603212183. The reversal of 165603212181 is 181212306561.

165603212181 is a `hidden beast` number, since 1 + 6 + 5 + 603 + 21 + 21 + 8 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (165603212179) and next prime (165603212183).

It is not a de Polignac number, because 165603212181 - 2¹ = 165603212179 is a prime.

It is a super-2 number, since 2×165603212181² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165603212183) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 92930205 + ... + 92931986.

Almost surely, 2^165603212181 is an apocalyptic number.

165603212181 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165603212181 is a deficient number, since it is larger than the sum of its proper divisors (104268690603).

165603212181 is a wasteful number, since it uses less digits than its factorization.

165603212181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185862214 (or 185862205 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The spelling of 165603212181 in words is "one hundred sixty-five billion, six hundred three million, two hundred twelve thousand, one hundred eighty-one".