221520213 has 12 divisors (see below), whose sum is σ = 324481248. Its totient is φ = 145599720.

The previous prime is 221520193. The next prime is 221520223. The reversal of 221520213 is 312025122.

It is not a de Polignac number, because 221520213 - 2¹⁰ = 221519189 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221520223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 172695 + ... + 173972.

It is an arithmetic number, because the mean of its divisors is an integer number (27040104).

Almost surely, 2^221520213 is an apocalyptic number.

It is an amenable number.

221520213 is a deficient number, since it is larger than the sum of its proper divisors (102961035).

221520213 is a wasteful number, since it uses less digits than its factorization.

221520213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346744 (or 346741 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 221520213 is about 14883.5551196614. Note that the first 3 decimals coincide. The cubic root of 221520213 is about 605.0683737583.

Adding to 221520213 its reverse (312025122), we get a palindrome (533545335).

The spelling of 221520213 in words is "two hundred twenty-one million, five hundred twenty thousand, two hundred thirteen".