158221 has 6 divisors (see below), whose sum is σ = 184110. Its totient is φ = 135576.

The previous prime is 158209. The next prime is 158227. The reversal of 158221 is 122851.

It can be written as a sum of positive squares in only one way, i.e., 122500 + 35721 = 350^2 + 189^2 .

It is not a de Polignac number, because 158221 - 2⁵ = 158189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (158227) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1566 + ... + 1663.

It is an arithmetic number, because the mean of its divisors is an integer number (30685).

2¹⁵⁸²²¹ is an apocalyptic number.

It is an amenable number.

158221 is a deficient number, since it is larger than the sum of its proper divisors (25889).

158221 is an equidigital number, since it uses as much as digits as its factorization.

158221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3243 (or 3236 counting only the distinct ones).

The product of its digits is 160, while the sum is 19.

The square root of 158221 is about 397.7700340649. The cubic root of 158221 is about 54.0863957648.

The spelling of 158221 in words is "one hundred fifty-eight thousand, two hundred twenty-one".