217430245 has 4 divisors (see below), whose sum is σ = 260916300. Its totient is φ = 173944192.

The previous prime is 217430207. The next prime is 217430267. The reversal of 217430245 is 542034712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 147841281 + 69588964 = 12159^2 + 8342^2 .

It is a cyclic number.

It is not a de Polignac number, because 217430245 - 2⁷ = 217430117 is a prime.

It is a super-2 number, since 2×217430245² = 94551822881520050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21743020 + ... + 21743029.

It is an arithmetic number, because the mean of its divisors is an integer number (65229075).

Almost surely, 2^217430245 is an apocalyptic number.

It is an amenable number.

217430245 is a deficient number, since it is larger than the sum of its proper divisors (43486055).

217430245 is an equidigital number, since it uses as much as digits as its factorization.

217430245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43486054.

The product of its (nonzero) digits is 6720, while the sum is 28.

The square root of 217430245 is about 14745.5160981228. The cubic root of 217430245 is about 601.3213886762.

Adding to 217430245 its reverse (542034712), we get a palindrome (759464957).

The spelling of 217430245 in words is "two hundred seventeen million, four hundred thirty thousand, two hundred forty-five".