221709233 has 6 divisors (see below), whose sum is σ = 233992674. Its totient is φ = 210039984.

The previous prime is 221709211. The next prime is 221709239. The reversal of 221709233 is 332907122.

221709233 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 only one way, i.e., 149255089 + 72454144 = 12217^2 + 8512^2 .

It is not a de Polignac number, because 221709233 - 2¹⁰ = 221708209 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221709196 and 221709205.

It is not an unprimeable number, because it can be changed into a prime (221709239) 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, 306716 + ... + 307437.

It is an arithmetic number, because the mean of its divisors is an integer number (38998779).

Almost surely, 2^221709233 is an apocalyptic number.

It is an amenable number.

221709233 is a deficient number, since it is larger than the sum of its proper divisors (12283441).

221709233 is an equidigital number, since it uses as much as digits as its factorization.

221709233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 614191 (or 614172 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 29.

The square root of 221709233 is about 14889.9037270225. The cubic root of 221709233 is about 605.2404235346.

The spelling of 221709233 in words is "two hundred twenty-one million, seven hundred nine thousand, two hundred thirty-three".