221868213 has 16 divisors (see below), whose sum is σ = 342160896. Its totient is φ = 125253360.

The previous prime is 221868167. The next prime is 221868217. The reversal of 221868213 is 312868122.

It is not a de Polignac number, because 221868213 - 2⁸ = 221867957 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 (221868217) 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, 61903 + ... + 65388.

It is an arithmetic number, because the mean of its divisors is an integer number (21385056).

Almost surely, 2^221868213 is an apocalyptic number.

It is an amenable number.

221868213 is a deficient number, since it is larger than the sum of its proper divisors (120292683).

221868213 is a wasteful number, since it uses less digits than its factorization.

221868213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127384.

The product of its digits is 9216, while the sum is 33.

The square root of 221868213 is about 14895.2412870688. The cubic root of 221868213 is about 605.3850546076.

Subtracting 221868213 from its reverse (312868122), we obtain a palindrome (90999909).

The spelling of 221868213 in words is "two hundred twenty-one million, eight hundred sixty-eight thousand, two hundred thirteen".