221538241 has 4 divisors (see below), whose sum is σ = 221833984. Its totient is φ = 221242500.

The previous prime is 221538227. The next prime is 221538253. The reversal of 221538241 is 142835122.

221538241 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221538241 - 2¹¹ = 221536193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221538281) 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, 146745 + ... + 148246.

It is an arithmetic number, because the mean of its divisors is an integer number (55458496).

Almost surely, 2^221538241 is an apocalyptic number.

It is an amenable number.

221538241 is a deficient number, since it is larger than the sum of its proper divisors (295743).

221538241 is an equidigital number, since it uses as much as digits as its factorization.

221538241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295742.

The product of its digits is 3840, while the sum is 28.

The square root of 221538241 is about 14884.1607422118. The cubic root of 221538241 is about 605.0847874248.

The spelling of 221538241 in words is "two hundred twenty-one million, five hundred thirty-eight thousand, two hundred forty-one".