168181993 has 8 divisors (see below), whose sum is σ = 195077312. Its totient is φ = 142004016.

The previous prime is 168181967. The next prime is 168182023. The reversal of 168181993 is 399181861.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 168181993 - 2⁵ = 168181961 is a prime.

It is the 12969-th Hogben number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (168181393) by changing a digit.

It is a nontrivial repunit in base 12968.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 178830 + ... + 179767.

It is an arithmetic number, because the mean of its divisors is an integer number (24384664).

Almost surely, 2^168181993 is an apocalyptic number.

It is an amenable number.

168181993 is a deficient number, since it is larger than the sum of its proper divisors (26895319).

168181993 is an equidigital number, since it uses as much as digits as its factorization.

168181993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 358671.

The product of its digits is 93312, while the sum is 46.

The square root of 168181993 is about 12968.5000289162. The cubic root of 168181993 is about 551.9840113429.

The spelling of 168181993 in words is "one hundred sixty-eight million, one hundred eighty-one thousand, nine hundred ninety-three".