71684009 has 2 divisors, whose sum is σ = 71684010. Its totient is φ = 71684008.

The previous prime is 71684003. The next prime is 71684021. The reversal of 71684009 is 90048617.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 68425984 + 3258025 = 8272^2 + 1805^2 .

It is an emirp because it is prime and its reverse (90048617) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71684009 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 71684009.

It is not a weakly prime, because it can be changed into another prime (71684003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35842004 + 35842005.

It is an arithmetic number, because the mean of its divisors is an integer number (35842005).

Almost surely, 2^71684009 is an apocalyptic number.

It is an amenable number.

71684009 is a deficient number, since it is larger than the sum of its proper divisors (1).

71684009 is an equidigital number, since it uses as much as digits as its factorization.

71684009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 71684009 is about 8466.6409514045. The cubic root of 71684009 is about 415.4072723150.

The spelling of 71684009 in words is "seventy-one million, six hundred eighty-four thousand, nine".