217024981 has 2 divisors, whose sum is σ = 217024982. Its totient is φ = 217024980.

The previous prime is 217024979. The next prime is 217025021. The reversal of 217024981 is 189420712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 124211025 + 92813956 = 11145^2 + 9634^2 .

It is a cyclic number.

It is not a de Polignac number, because 217024981 - 2¹ = 217024979 is a prime.

It is a super-2 number, since 2×217024981² = 94199684756100722, which contains 22 as substring.

Together with 217024979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217025981) by changing a digit.

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 as a sum of consecutive naturals, namely, 108512490 + 108512491.

It is an arithmetic number, because the mean of its divisors is an integer number (108512491).

Almost surely, 2^217024981 is an apocalyptic number.

It is an amenable number.

217024981 is a deficient number, since it is larger than the sum of its proper divisors (1).

217024981 is an equidigital number, since it uses as much as digits as its factorization.

217024981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8064, while the sum is 34.

The square root of 217024981 is about 14731.7677486444. The cubic root of 217024981 is about 600.9475592462.

The spelling of 217024981 in words is "two hundred seventeen million, twenty-four thousand, nine hundred eighty-one".