217871432289 has 135 divisors (see below), whose sum is σ = 392849485281. Its totient is φ = 119977789680.

The previous prime is 217871432281. The next prime is 217871432323. The reversal of 217871432289 is 982234178712.

The square root of 217871432289 is 466767.

It is a perfect power (a square), and thus also a powerful number.

217871432289 is a `hidden beast` number, since 2 + 178 + 71 + 4 + 322 + 89 = 666.

It is not a de Polignac number, because 217871432289 - 2³ = 217871432281 is a prime.

It is a super-2 number, since 2×217871432289² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (217871432281) by changing a digit.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 911595832 + ... + 911596070.

Almost surely, 2^217871432289 is an apocalyptic number.

217871432289 is the 466767-th square number.

217871432289 is the 233384-th centered octagonal number.

It is an amenable number.

217871432289 is a deficient number, since it is larger than the sum of its proper divisors (174978052992).

217871432289 is an frugal number, since it uses more digits than its factorization.

217871432289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 566 (or 280 counting only the distinct ones).

The product of its digits is 2709504, while the sum is 54.

The spelling of 217871432289 in words is "two hundred seventeen billion, eight hundred seventy-one million, four hundred thirty-two thousand, two hundred eighty-nine".