217920098321689 has 3 divisors (see below), whose sum is σ = 217920113083807. Its totient is φ = 217920083559572.

The previous prime is 217920098321687. The next prime is 217920098321743. The reversal of 217920098321689 is 986123890029712.

The square root of 217920098321689 is 14762117.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 217398658358025 + 521439963664 = 14744445^2 + 722108^2 .

It is not a de Polignac number, because 217920098321689 - 2¹ = 217920098321687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217920098321687) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 7381059 + ... + 22143175.

Almost surely, 2^{217920098321689} is an apocalyptic number.

217920098321689 is the 14762117-th square number.

217920098321689 is the 7381059-th centered octagonal number.

It is an amenable number.

217920098321689 is a deficient number, since it is larger than the sum of its proper divisors (14762118).

217920098321689 is an frugal number, since it uses more digits than its factorization.

217920098321689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29524234 (or 14762117 counting only the distinct ones).

The product of its (nonzero) digits is 47029248, while the sum is 67.

The spelling of 217920098321689 in words is "two hundred seventeen trillion, nine hundred twenty billion, ninety-eight million, three hundred twenty-one thousand, six hundred eighty-nine".