217157389 has 2 divisors, whose sum is σ = 217157390. Its totient is φ = 217157388.

The previous prime is 217157383. The next prime is 217157399. The reversal of 217157389 is 983751712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 217061289 + 96100 = 14733^2 + 310^2 .

It is a cyclic number.

It is not a de Polignac number, because 217157389 - 2¹³ = 217149197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217157383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108578694 + 108578695.

It is an arithmetic number, because the mean of its divisors is an integer number (108578695).

Almost surely, 2^217157389 is an apocalyptic number.

It is an amenable number.

217157389 is a deficient number, since it is larger than the sum of its proper divisors (1).

217157389 is an equidigital number, since it uses as much as digits as its factorization.

217157389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 105840, while the sum is 43.

The square root of 217157389 is about 14736.2610251040. The cubic root of 217157389 is about 601.0697480797.

The spelling of 217157389 in words is "two hundred seventeen million, one hundred fifty-seven thousand, three hundred eighty-nine".