1716721309 has 2 divisors, whose sum is σ = 1716721310. Its totient is φ = 1716721308.

The previous prime is 1716721273. The next prime is 1716721313. The reversal of 1716721309 is 9031276171.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1538365284 + 178356025 = 39222^2 + 13355^2 .

It is a cyclic number.

It is not a de Polignac number, because 1716721309 - 2¹⁵ = 1716688541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1716721009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 858360654 + 858360655.

It is an arithmetic number, because the mean of its divisors is an integer number (858360655).

Almost surely, 2^1716721309 is an apocalyptic number.

It is an amenable number.

1716721309 is a deficient number, since it is larger than the sum of its proper divisors (1).

1716721309 is an equidigital number, since it uses as much as digits as its factorization.

1716721309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15876, while the sum is 37.

The square root of 1716721309 is about 41433.3357213730. The cubic root of 1716721309 is about 1197.3834909450.

The spelling of 1716721309 in words is "one billion, seven hundred sixteen million, seven hundred twenty-one thousand, three hundred nine".