213156221 has 2 divisors, whose sum is σ = 213156222. Its totient is φ = 213156220.

The previous prime is 213156199. The next prime is 213156247. The reversal of 213156221 is 122651312.

213156221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 204890596 + 8265625 = 14314^2 + 2875^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213156221 is a prime.

It is a super-3 number, since 3×213156221³ (a number of 26 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213156721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106578110 + 106578111.

It is an arithmetic number, because the mean of its divisors is an integer number (106578111).

Almost surely, 2^213156221 is an apocalyptic number.

It is an amenable number.

213156221 is a deficient number, since it is larger than the sum of its proper divisors (1).

213156221 is an equidigital number, since it uses as much as digits as its factorization.

213156221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720, while the sum is 23.

The square root of 213156221 is about 14599.8705816182. The cubic root of 213156221 is about 597.3552304153.

The spelling of 213156221 in words is "two hundred thirteen million, one hundred fifty-six thousand, two hundred twenty-one".