156221 has 8 divisors (see below), whose sum is σ = 171864. Its totient is φ = 141120.

The previous prime is 156217. The next prime is 156227. The reversal of 156221 is 122651.

156221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 7225 + 148996 = 85^2 + 386^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 156221 - 2² = 156217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 156221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (156227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 695 + ... + 891.

It is an arithmetic number, because the mean of its divisors is an integer number (21483).

2¹⁵⁶²²¹ is an apocalyptic number.

It is an amenable number.

156221 is a deficient number, since it is larger than the sum of its proper divisors (15643).

156221 is a wasteful number, since it uses less digits than its factorization.

156221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271.

The product of its digits is 120, while the sum is 17.

The square root of 156221 is about 395.2480233980. The cubic root of 156221 is about 53.8575348523.

Adding to 156221 its reverse (122651), we get a palindrome (278872).

The spelling of 156221 in words is "one hundred fifty-six thousand, two hundred twenty-one".