161813 has 4 divisors (see below), whose sum is σ = 163488. Its totient is φ = 160140.

The previous prime is 161807. The next prime is 161831. The reversal of 161813 is 318161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 161813 - 2¹⁰ = 160789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161873) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 683 + ... + 888.

It is an arithmetic number, because the mean of its divisors is an integer number (40872).

2¹⁶¹⁸¹³ is an apocalyptic number.

It is an amenable number.

161813 is a deficient number, since it is larger than the sum of its proper divisors (1675).

161813 is a wasteful number, since it uses less digits than its factorization.

161813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1674.

The product of its digits is 144, while the sum is 20.

The square root of 161813 is about 402.2598662556. The cubic root of 161813 is about 54.4926343046.

Adding to 161813 its reverse (318161), we get a palindrome (479974).

The spelling of 161813 in words is "one hundred sixty-one thousand, eight hundred thirteen".