201720196787 has 2 divisors, whose sum is σ = 201720196788. Its totient is φ = 201720196786.

The previous prime is 201720196747. The next prime is 201720196823. The reversal of 201720196787 is 787691027102.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 201720196787 - 2¹⁰ = 201720195763 is a prime.

It is not a weakly prime, because it can be changed into another prime (201720196747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100860098393 + 100860098394.

It is an arithmetic number, because the mean of its divisors is an integer number (100860098394).

Almost surely, 2^201720196787 is an apocalyptic number.

201720196787 is a deficient number, since it is larger than the sum of its proper divisors (1).

201720196787 is an equidigital number, since it uses as much as digits as its factorization.

201720196787 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 592704, while the sum is 50.

The spelling of 201720196787 in words is "two hundred one billion, seven hundred twenty million, one hundred ninety-six thousand, seven hundred eighty-seven".