71663609 has 2 divisors, whose sum is σ = 71663610. Its totient is φ = 71663608.

The previous prime is 71663597. The next prime is 71663617. The reversal of 71663609 is 90636617.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66373609 + 5290000 = 8147^2 + 2300^2 .

It is an emirp because it is prime and its reverse (90636617) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71663609 - 2¹⁶ = 71598073 is a prime.

It is not a weakly prime, because it can be changed into another prime (71663629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35831804 + 35831805.

It is an arithmetic number, because the mean of its divisors is an integer number (35831805).

Almost surely, 2^71663609 is an apocalyptic number.

It is an amenable number.

71663609 is a deficient number, since it is larger than the sum of its proper divisors (1).

71663609 is an equidigital number, since it uses as much as digits as its factorization.

71663609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 38.

The square root of 71663609 is about 8465.4361376128. The cubic root of 71663609 is about 415.3678627244.

The spelling of 71663609 in words is "seventy-one million, six hundred sixty-three thousand, six hundred nine".