71136809 has 2 divisors, whose sum is σ = 71136810. Its totient is φ = 71136808.

The previous prime is 71136787. The next prime is 71136827. The reversal of 71136809 is 90863117.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71031184 + 105625 = 8428^2 + 325^2 .

It is a cyclic number.

It is not a de Polignac number, because 71136809 - 2²⁴ = 54359593 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (71136859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35568404 + 35568405.

It is an arithmetic number, because the mean of its divisors is an integer number (35568405).

Almost surely, 2^71136809 is an apocalyptic number.

It is an amenable number.

71136809 is a deficient number, since it is larger than the sum of its proper divisors (1).

71136809 is an equidigital number, since it uses as much as digits as its factorization.

71136809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 71136809 is about 8434.2639868574. The cubic root of 71136809 is about 414.3475672724.

The spelling of 71136809 in words is "seventy-one million, one hundred thirty-six thousand, eight hundred nine".