9161221 has 4 divisors (see below), whose sum is σ = 9194572. Its totient is φ = 9127872.

The previous prime is 9161219. The next prime is 9161239. The reversal of 9161221 is 1221619.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2856100 + 6305121 = 1690^2 + 2511^2 .

It is a cyclic number.

It is not a de Polignac number, because 9161221 - 2¹ = 9161219 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 9161192 and 9161201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9161261) 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, 16260 + ... + 16813.

It is an arithmetic number, because the mean of its divisors is an integer number (2298643).

Almost surely, 2^9161221 is an apocalyptic number.

It is an amenable number.

9161221 is a deficient number, since it is larger than the sum of its proper divisors (33351).

9161221 is a wasteful number, since it uses less digits than its factorization.

9161221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33350.

The product of its digits is 216, while the sum is 22.

The square root of 9161221 is about 3026.7508982406. The cubic root of 9161221 is about 209.2430876521.

The spelling of 9161221 in words is "nine million, one hundred sixty-one thousand, two hundred twenty-one".