221505161 has 16 divisors (see below), whose sum is σ = 234057600. Its totient is φ = 209328000.

The previous prime is 221505139. The next prime is 221505191. The reversal of 221505161 is 161505122.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 221505161 - 2¹⁴ = 221488777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221505131) 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, 368261 + ... + 368861.

It is an arithmetic number, because the mean of its divisors is an integer number (14628600).

Almost surely, 2^221505161 is an apocalyptic number.

It is an amenable number.

221505161 is a deficient number, since it is larger than the sum of its proper divisors (12552439).

221505161 is a wasteful number, since it uses less digits than its factorization.

221505161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 880.

The product of its (nonzero) digits is 600, while the sum is 23.

The square root of 221505161 is about 14883.0494523132. The cubic root of 221505161 is about 605.0546689209.

The spelling of 221505161 in words is "two hundred twenty-one million, five hundred five thousand, one hundred sixty-one".