165993391939 has 8 divisors (see below), whose sum is σ = 168836336640. Its totient is φ = 163151430600.

The previous prime is 165993391933. The next prime is 165993391951. The reversal of 165993391939 is 939193399561.

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 165993391939 - 2⁹ = 165993391427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165993391933) 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, 98754 + ... + 584584.

It is an arithmetic number, because the mean of its divisors is an integer number (21104542080).

Almost surely, 2^165993391939 is an apocalyptic number.

165993391939 is a deficient number, since it is larger than the sum of its proper divisors (2842944701).

165993391939 is an equidigital number, since it uses as much as digits as its factorization.

165993391939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491681.

The product of its digits is 47829690, while the sum is 67.

The spelling of 165993391939 in words is "one hundred sixty-five billion, nine hundred ninety-three million, three hundred ninety-one thousand, nine hundred thirty-nine".