71664709 has 2 divisors, whose sum is σ = 71664710. Its totient is φ = 71664708.

The previous prime is 71664661. The next prime is 71664721. The reversal of 71664709 is 90746617.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46444225 + 25220484 = 6815^2 + 5022^2 .

It is a cyclic number.

It is not a de Polignac number, because 71664709 - 2²¹ = 69567557 is a prime.

It is a zygodrome in base 3.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71664779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35832354 + 35832355.

It is an arithmetic number, because the mean of its divisors is an integer number (35832355).

Almost surely, 2^71664709 is an apocalyptic number.

It is an amenable number.

71664709 is a deficient number, since it is larger than the sum of its proper divisors (1).

71664709 is an equidigital number, since it uses as much as digits as its factorization.

71664709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 63504, while the sum is 40.

The square root of 71664709 is about 8465.5011074360. The cubic root of 71664709 is about 415.3699879421.

The spelling of 71664709 in words is "seventy-one million, six hundred sixty-four thousand, seven hundred nine".