165836440991 has 8 divisors (see below), whose sum is σ = 181108486944. Its totient is φ = 150923737440.

The previous prime is 165836440967. The next prime is 165836440993. The reversal of 165836440991 is 199044638561.

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 165836440991 - 2¹⁸ = 165836178847 is a prime.

It is a super-2 number, since 2×165836440991² (a number of 23 digits) contains 22 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 (165836440993) 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, 89834636 + ... + 89836481.

It is an arithmetic number, because the mean of its divisors is an integer number (22638560868).

Almost surely, 2^165836440991 is an apocalyptic number.

165836440991 is a deficient number, since it is larger than the sum of its proper divisors (15272045953).

165836440991 is a wasteful number, since it uses less digits than its factorization.

165836440991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 179671201.

The product of its (nonzero) digits is 5598720, while the sum is 56.

The spelling of 165836440991 in words is "one hundred sixty-five billion, eight hundred thirty-six million, four hundred forty thousand, nine hundred ninety-one".