221330021 has 16 divisors (see below), whose sum is σ = 259858368. Its totient is φ = 186259200.

The previous prime is 221329991. The next prime is 221330047. The reversal of 221330021 is 120033122.

It is a happy number.

221330021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 221330021 - 2⁶ = 221329957 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221329978 and 221330005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221330051) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1706 + ... + 21108.

It is an arithmetic number, because the mean of its divisors is an integer number (16241148).

Almost surely, 2^221330021 is an apocalyptic number.

It is an amenable number.

221330021 is a deficient number, since it is larger than the sum of its proper divisors (38528347).

221330021 is a wasteful number, since it uses less digits than its factorization.

221330021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19492.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 221330021 is about 14877.1644139601. The cubic root of 221330021 is about 604.8951583918.

Adding to 221330021 its reverse (120033122), we get a palindrome (341363143).

The spelling of 221330021 in words is "two hundred twenty-one million, three hundred thirty thousand, twenty-one".