161603221 has 16 divisors (see below), whose sum is σ = 183246336. Its totient is φ = 141394176.

The previous prime is 161603191. The next prime is 161603251. The reversal of 161603221 is 122306161.

It is an interprime number because it is at equal distance from previous prime (161603191) and next prime (161603251).

It is a cyclic number.

It is not a de Polignac number, because 161603221 - 2¹¹ = 161601173 is a prime.

It is a super-2 number, since 2×161603221² = 52231202075149682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161603192 and 161603201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161603251) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31396 + ... + 36178.

It is an arithmetic number, because the mean of its divisors is an integer number (11452896).

Almost surely, 2^161603221 is an apocalyptic number.

It is an amenable number.

161603221 is a deficient number, since it is larger than the sum of its proper divisors (21643115).

161603221 is a wasteful number, since it uses less digits than its factorization.

161603221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4932.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 161603221 is about 12712.3255543587. The cubic root of 161603221 is about 544.6907551785.

Adding to 161603221 its reverse (122306161), we get a palindrome (283909382).

The spelling of 161603221 in words is "one hundred sixty-one million, six hundred three thousand, two hundred twenty-one".