1716721681 has 8 divisors (see below), whose sum is σ = 1729528040. Its totient is φ = 1703939328.

The previous prime is 1716721667. The next prime is 1716721697. The reversal of 1716721681 is 1861276171.

It can be written as a sum of positive squares in 4 ways, for example, as 2016400 + 1714705281 = 1420^2 + 41409^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 1716721681 - 2⁹ = 1716721169 is a prime.

It is a super-2 number, since 2×1716721681² = 5894266660030931522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1716721621) 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, 152995 + ... + 163831.

It is an arithmetic number, because the mean of its divisors is an integer number (216191005).

Almost surely, 2^1716721681 is an apocalyptic number.

It is an amenable number.

1716721681 is a deficient number, since it is larger than the sum of its proper divisors (12806359).

1716721681 is a wasteful number, since it uses less digits than its factorization.

1716721681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12003.

The product of its digits is 28224, while the sum is 40.

The square root of 1716721681 is about 41433.3402105116. The cubic root of 1716721681 is about 1197.3835774328.

The spelling of 1716721681 in words is "one billion, seven hundred sixteen million, seven hundred twenty-one thousand, six hundred eighty-one".