201720709 has 2 divisors, whose sum is σ = 201720710. Its totient is φ = 201720708.

The previous prime is 201720683. The next prime is 201720721. The reversal of 201720709 is 907027102.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 195580225 + 6140484 = 13985^2 + 2478^2 .

It is a cyclic number.

It is not a de Polignac number, because 201720709 - 2⁵ = 201720677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201720769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100860354 + 100860355.

It is an arithmetic number, because the mean of its divisors is an integer number (100860355).

Almost surely, 2^201720709 is an apocalyptic number.

It is an amenable number.

201720709 is a deficient number, since it is larger than the sum of its proper divisors (1).

201720709 is an equidigital number, since it uses as much as digits as its factorization.

201720709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1764, while the sum is 28.

The square root of 201720709 is about 14202.8415818807. The cubic root of 201720709 is about 586.4758886320.

The spelling of 201720709 in words is "two hundred one million, seven hundred twenty thousand, seven hundred nine".