172816220728409 has 2 divisors, whose sum is σ = 172816220728410. Its totient is φ = 172816220728408.

The previous prime is 172816220728397. The next prime is 172816220728427. The reversal of 172816220728409 is 904827022618271.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 161680685098384 + 11135535630025 = 12715372^2 + 3336995^2 .

It is an emirp because it is prime and its reverse (904827022618271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 172816220728409 - 2²⁰ = 172816219679833 is a prime.

It is a super-2 number, since 2×172816220728409² (a number of 29 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (172816220728009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86408110364204 + 86408110364205.

It is an arithmetic number, because the mean of its divisors is an integer number (86408110364205).

Almost surely, 2^{172816220728409} is an apocalyptic number.

It is an amenable number.

172816220728409 is a deficient number, since it is larger than the sum of its proper divisors (1).

172816220728409 is an equidigital number, since it uses as much as digits as its factorization.

172816220728409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10838016, while the sum is 59.

The spelling of 172816220728409 in words is "one hundred seventy-two trillion, eight hundred sixteen billion, two hundred twenty million, seven hundred twenty-eight thousand, four hundred nine".