165133941681 has 4 divisors (see below), whose sum is σ = 220178588912. Its totient is φ = 110089294452.

The previous prime is 165133941677. The next prime is 165133941751. The reversal of 165133941681 is 186149331561.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 186149331561 = 3 ⋅62049777187.

It is not a de Polignac number, because 165133941681 - 2² = 165133941677 is a prime.

It is a super-2 number, since 2×165133941681² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 165133941681.

It is not an unprimeable number, because it can be changed into a prime (165133941601) 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, 27522323611 + ... + 27522323616.

It is an arithmetic number, because the mean of its divisors is an integer number (55044647228).

Almost surely, 2^165133941681 is an apocalyptic number.

It is an amenable number.

165133941681 is a deficient number, since it is larger than the sum of its proper divisors (55044647231).

165133941681 is an equidigital number, since it uses as much as digits as its factorization.

165133941681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55044647230.

The product of its digits is 466560, while the sum is 48.

The spelling of 165133941681 in words is "one hundred sixty-five billion, one hundred thirty-three million, nine hundred forty-one thousand, six hundred eighty-one".