161635 has 4 divisors (see below), whose sum is σ = 193968. Its totient is φ = 129304.

The previous prime is 161627. The next prime is 161639. The reversal of 161635 is 536161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 536161 = 19 ⋅28219.

It is a cyclic number.

It is not a de Polignac number, because 161635 - 2³ = 161627 is a prime.

It is a super-2 number, since 2×161635² = 52251746450, which contains 22 as substring.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16159 + ... + 16168.

It is an arithmetic number, because the mean of its divisors is an integer number (48492).

2¹⁶¹⁶³⁵ is an apocalyptic number.

161635 is a deficient number, since it is larger than the sum of its proper divisors (32333).

161635 is an equidigital number, since it uses as much as digits as its factorization.

161635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32332.

The product of its digits is 540, while the sum is 22.

The square root of 161635 is about 402.0385553650. The cubic root of 161635 is about 54.4726457010.

Adding to 161635 its reverse (536161), we get a palindrome (697796).

The spelling of 161635 in words is "one hundred sixty-one thousand, six hundred thirty-five".