165836642281 has 4 divisors (see below), whose sum is σ = 170318713732. Its totient is φ = 161354570832.

The previous prime is 165836642249. The next prime is 165836642297. The reversal of 165836642281 is 182246638561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 111545312256 + 54291330025 = 333984^2 + 233005^2 .

It is a cyclic number.

It is not a de Polignac number, because 165836642281 - 2⁵ = 165836642249 is a prime.

It is a super-2 number, since 2×165836642281² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165836642201) 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, 2241035670 + ... + 2241035743.

It is an arithmetic number, because the mean of its divisors is an integer number (42579678433).

Almost surely, 2^165836642281 is an apocalyptic number.

It is an amenable number.

165836642281 is a deficient number, since it is larger than the sum of its proper divisors (4482071451).

165836642281 is an equidigital number, since it uses as much as digits as its factorization.

165836642281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4482071450.

The product of its digits is 3317760, while the sum is 52.

The spelling of 165836642281 in words is "one hundred sixty-five billion, eight hundred thirty-six million, six hundred forty-two thousand, two hundred eighty-one".