161993 has 8 divisors (see below), whose sum is σ = 184968. Its totient is φ = 140544.

The previous prime is 161983. The next prime is 161999. The reversal of 161993 is 399161.

161993 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 61504 + 100489 = 248^2 + 317^2 .

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 161993 - 2⁴ = 161977 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161999) 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, 146 + ... + 587.

It is an arithmetic number, because the mean of its divisors is an integer number (23121).

2¹⁶¹⁹⁹³ is an apocalyptic number.

161993 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

161993 is a deficient number, since it is larger than the sum of its proper divisors (22975).

161993 is a wasteful number, since it uses less digits than its factorization.

161993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 763.

The product of its digits is 1458, while the sum is 29.

The square root of 161993 is about 402.4835400361. The cubic root of 161993 is about 54.5128325981.

The spelling of 161993 in words is "one hundred sixty-one thousand, nine hundred ninety-three".