213123221 has 8 divisors (see below), whose sum is σ = 223098624. Its totient is φ = 203206960.

The previous prime is 213123217. The next prime is 213123223. The reversal of 213123221 is 122321312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 213123221 - 2² = 213123217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 213123221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213123223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7325 + ... + 21906.

It is an arithmetic number, because the mean of its divisors is an integer number (27887328).

Almost surely, 2^213123221 is an apocalyptic number.

It is an amenable number.

213123221 is a deficient number, since it is larger than the sum of its proper divisors (9975403).

213123221 is a wasteful number, since it uses less digits than its factorization.

213123221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29571.

The product of its digits is 144, while the sum is 17.

The square root of 213123221 is about 14598.7403908693. The cubic root of 213123221 is about 597.3244021025.

Adding to 213123221 its reverse (122321312), we get a palindrome (335444533).

It can be divided in two parts, 2131 and 23221, that added together give a palindrome (25352).

The spelling of 213123221 in words is "two hundred thirteen million, one hundred twenty-three thousand, two hundred twenty-one".