221523221 has 8 divisors (see below), whose sum is σ = 222676224. Its totient is φ = 220374000.

The previous prime is 221523193. The next prime is 221523251. The reversal of 221523221 is 122325122.

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 221523221 - 2⁶ = 221523157 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221523193 and 221523202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221523251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 294596 + ... + 295346.

It is an arithmetic number, because the mean of its divisors is an integer number (27834528).

Almost surely, 2^221523221 is an apocalyptic number.

It is an amenable number.

221523221 is a deficient number, since it is larger than the sum of its proper divisors (1153003).

221523221 is an equidigital number, since it uses as much as digits as its factorization.

221523221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1891.

The product of its digits is 480, while the sum is 20.

The square root of 221523221 is about 14883.6561704441. The cubic root of 221523221 is about 605.0711124661.

Adding to 221523221 its reverse (122325122), we get a palindrome (343848343).

The spelling of 221523221 in words is "two hundred twenty-one million, five hundred twenty-three thousand, two hundred twenty-one".