217030381 has 8 divisors (see below), whose sum is σ = 230754744. Its totient is φ = 203412480.

The previous prime is 217030357. The next prime is 217030409. The reversal of 217030381 is 183030712.

It can be written as a sum of positive squares in 4 ways, for example, as 133033156 + 83997225 = 11534^2 + 9165^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 217030381 - 2¹¹ = 217028333 is a prime.

It is a super-2 number, since 2×217030381² = 94204372554010322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217030321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22390 + ... + 30583.

It is an arithmetic number, because the mean of its divisors is an integer number (28844343).

Almost surely, 2^217030381 is an apocalyptic number.

It is an amenable number.

217030381 is a deficient number, since it is larger than the sum of its proper divisors (13724363).

217030381 is a wasteful number, since it uses less digits than its factorization.

217030381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53231.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 217030381 is about 14731.9510248982. The cubic root of 217030381 is about 600.9525434495.

The spelling of 217030381 in words is "two hundred seventeen million, thirty thousand, three hundred eighty-one".