71813909 has 2 divisors, whose sum is σ = 71813910. Its totient is φ = 71813908.

The previous prime is 71813881. The next prime is 71813921. The reversal of 71813909 is 90931817.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43692100 + 28121809 = 6610^2 + 5303^2 .

It is an emirp because it is prime and its reverse (90931817) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71813909 - 2¹⁶ = 71748373 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71813009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35906954 + 35906955.

It is an arithmetic number, because the mean of its divisors is an integer number (35906955).

Almost surely, 2^71813909 is an apocalyptic number.

It is an amenable number.

71813909 is a deficient number, since it is larger than the sum of its proper divisors (1).

71813909 is an equidigital number, since it uses as much as digits as its factorization.

71813909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13608, while the sum is 38.

The square root of 71813909 is about 8474.3087623711. The cubic root of 71813909 is about 415.6580434580.

The spelling of 71813909 in words is "seventy-one million, eight hundred thirteen thousand, nine hundred nine".