217070509 has 2 divisors, whose sum is σ = 217070510. Its totient is φ = 217070508.

The previous prime is 217070479. The next prime is 217070521. The reversal of 217070509 is 905070712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 207273609 + 9796900 = 14397^2 + 3130^2 .

It is a cyclic number.

It is not a de Polignac number, because 217070509 - 2¹³ = 217062317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217070599) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108535254 + 108535255.

It is an arithmetic number, because the mean of its divisors is an integer number (108535255).

Almost surely, 2^217070509 is an apocalyptic number.

It is an amenable number.

217070509 is a deficient number, since it is larger than the sum of its proper divisors (1).

217070509 is an equidigital number, since it uses as much as digits as its factorization.

217070509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4410, while the sum is 31.

The square root of 217070509 is about 14733.3128996842. The cubic root of 217070509 is about 600.9895790287.

The spelling of 217070509 in words is "two hundred seventeen million, seventy thousand, five hundred nine".