161223205 has 32 divisors (see below), whose sum is σ = 228251520. Its totient is φ = 107777280.

The previous prime is 161223187. The next prime is 161223217. The reversal of 161223205 is 502322161.

It is not a de Polignac number, because 161223205 - 2⁹ = 161222693 is a prime.

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 316491 + ... + 316999.

It is an arithmetic number, because the mean of its divisors is an integer number (7132860).

Almost surely, 2^161223205 is an apocalyptic number.

It is an amenable number.

161223205 is a deficient number, since it is larger than the sum of its proper divisors (67028315).

161223205 is a wasteful number, since it uses less digits than its factorization.

161223205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 981.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 161223205 is about 12697.3700032723. The cubic root of 161223205 is about 544.2634665345.

Adding to 161223205 its reverse (502322161), we get a palindrome (663545366).

It can be divided in two parts, 16 and 1223205, that added together give a palindrome (1223221).

The spelling of 161223205 in words is "one hundred sixty-one million, two hundred twenty-three thousand, two hundred five".