221543213 has 4 divisors (see below), whose sum is σ = 226946748. Its totient is φ = 216139680.

The previous prime is 221543159. The next prime is 221543219. The reversal of 221543213 is 312345122.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6568969 + 214974244 = 2563^2 + 14662^2 .

It is a cyclic number.

It is not a de Polignac number, because 221543213 - 2⁶ = 221543149 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221543219) 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, 2701706 + ... + 2701787.

It is an arithmetic number, because the mean of its divisors is an integer number (56736687).

Almost surely, 2^221543213 is an apocalyptic number.

It is an amenable number.

221543213 is a deficient number, since it is larger than the sum of its proper divisors (5403535).

221543213 is an equidigital number, since it uses as much as digits as its factorization.

221543213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5403534.

The product of its digits is 1440, while the sum is 23.

The square root of 221543213 is about 14884.3277644642. The cubic root of 221543213 is about 605.0893140460.

Adding to 221543213 its reverse (312345122), we get a palindrome (533888335).

The spelling of 221543213 in words is "two hundred twenty-one million, five hundred forty-three thousand, two hundred thirteen".