161603 has 8 divisors (see below), whose sum is σ = 180096. Its totient is φ = 144000.

The previous prime is 161599. The next prime is 161611. The reversal of 161603 is 306161.

It is a Cunningham number, because it is equal to 402²-1.

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 161603 - 2² = 161599 is a prime.

It is a super-2 number, since 2×161603² = 52231059218, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161683) 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, 203 + ... + 603.

It is an arithmetic number, because the mean of its divisors is an integer number (22512).

2¹⁶¹⁶⁰³ is an apocalyptic number.

161603 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

161603 is a deficient number, since it is larger than the sum of its proper divisors (18493).

161603 is a wasteful number, since it uses less digits than its factorization.

161603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 445.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 161603 is about 401.9987562170. The cubic root of 161603 is about 54.4690506882.

Adding to 161603 its reverse (306161), we get a palindrome (467764).

The spelling of 161603 in words is "one hundred sixty-one thousand, six hundred three".