71728109 has 2 divisors, whose sum is σ = 71728110. Its totient is φ = 71728108.

The previous prime is 71728093. The next prime is 71728169. The reversal of 71728109 is 90182717.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62758084 + 8970025 = 7922^2 + 2995^2 .

It is an emirp because it is prime and its reverse (90182717) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71728109 - 2⁴ = 71728093 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71728169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35864054 + 35864055.

It is an arithmetic number, because the mean of its divisors is an integer number (35864055).

Almost surely, 2^71728109 is an apocalyptic number.

It is an amenable number.

71728109 is a deficient number, since it is larger than the sum of its proper divisors (1).

71728109 is an equidigital number, since it uses as much as digits as its factorization.

71728109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7056, while the sum is 35.

The square root of 71728109 is about 8469.2448895991. The cubic root of 71728109 is about 415.4924410323.

The spelling of 71728109 in words is "seventy-one million, seven hundred twenty-eight thousand, one hundred nine".