9158221 has 2 divisors, whose sum is σ = 9158222. Its totient is φ = 9158220.

The previous prime is 9158213. The next prime is 9158231. The reversal of 9158221 is 1228519.

9158221 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6817321 + 2340900 = 2611^2 + 1530^2 .

It is an emirp because it is prime and its reverse (1228519) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9158221 - 2³ = 9158213 is a prime.

9158221 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 9158221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9158231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4579110 + 4579111.

It is an arithmetic number, because the mean of its divisors is an integer number (4579111).

Almost surely, 2^9158221 is an apocalyptic number.

It is an amenable number.

9158221 is a deficient number, since it is larger than the sum of its proper divisors (1).

9158221 is an equidigital number, since it uses as much as digits as its factorization.

9158221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 28.

The square root of 9158221 is about 3026.2552767405. The cubic root of 9158221 is about 209.2202450712.

The spelling of 9158221 in words is "nine million, one hundred fifty-eight thousand, two hundred twenty-one".