213217221 has 32 divisors (see below), whose sum is σ = 343526400. Its totient is φ = 114912000.

The previous prime is 213217219. The next prime is 213217231. The reversal of 213217221 is 122712312.

It is not a de Polignac number, because 213217221 - 2¹ = 213217219 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213217231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 99085 + ... + 101213.

It is an arithmetic number, because the mean of its divisors is an integer number (10735200).

Almost surely, 2^213217221 is an apocalyptic number.

213217221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

213217221 is a deficient number, since it is larger than the sum of its proper divisors (130309179).

213217221 is a wasteful number, since it uses less digits than its factorization.

213217221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2409.

The product of its digits is 336, while the sum is 21.

The square root of 213217221 is about 14601.9594917942. The cubic root of 213217221 is about 597.4122077088.

Adding to 213217221 its reverse (122712312), we get a palindrome (335929533).

The spelling of 213217221 in words is "two hundred thirteen million, two hundred seventeen thousand, two hundred twenty-one".