71789909 has 2 divisors, whose sum is σ = 71789910. Its totient is φ = 71789908.

The previous prime is 71789899. The next prime is 71789911. The reversal of 71789909 is 90998717.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42120100 + 29669809 = 6490^2 + 5447^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71789909 is a prime.

Together with 71789911, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71789989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35894954 + 35894955.

It is an arithmetic number, because the mean of its divisors is an integer number (35894955).

Almost surely, 2^71789909 is an apocalyptic number.

It is an amenable number.

71789909 is a deficient number, since it is larger than the sum of its proper divisors (1).

71789909 is an equidigital number, since it uses as much as digits as its factorization.

71789909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 285768, while the sum is 50.

The square root of 71789909 is about 8472.8925993429. The cubic root of 71789909 is about 415.6117343949.

The spelling of 71789909 in words is "seventy-one million, seven hundred eighty-nine thousand, nine hundred nine".