217070221 has 2 divisors, whose sum is σ = 217070222. Its totient is φ = 217070220.

The previous prime is 217070179. The next prime is 217070233. The reversal of 217070221 is 122070712.

217070221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 213014025 + 4056196 = 14595^2 + 2014^2 .

It is a cyclic number.

It is not a de Polignac number, because 217070221 - 2²¹ = 214973069 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 217070192 and 217070201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217070281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108535110 + 108535111.

It is an arithmetic number, because the mean of its divisors is an integer number (108535111).

Almost surely, 2^217070221 is an apocalyptic number.

It is an amenable number.

217070221 is a deficient number, since it is larger than the sum of its proper divisors (1).

217070221 is an equidigital number, since it uses as much as digits as its factorization.

217070221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 392, while the sum is 22.

The square root of 217070221 is about 14733.3031259117. The cubic root of 217070221 is about 600.9893132393.

The spelling of 217070221 in words is "two hundred seventeen million, seventy thousand, two hundred twenty-one".