71123831509 has 4 divisors (see below), whose sum is σ = 71139128320. Its totient is φ = 71108534700.

The previous prime is 71123831501. The next prime is 71123831531. The reversal of 71123831509 is 90513832117.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 71123831509 - 2³ = 71123831501 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71123831501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7641429 + ... + 7650730.

It is an arithmetic number, because the mean of its divisors is an integer number (17784782080).

Almost surely, 2^71123831509 is an apocalyptic number.

It is an amenable number.

71123831509 is a deficient number, since it is larger than the sum of its proper divisors (15296811).

71123831509 is a wasteful number, since it uses less digits than its factorization.

71123831509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15296810.

The product of its (nonzero) digits is 45360, while the sum is 40.

The spelling of 71123831509 in words is "seventy-one billion, one hundred twenty-three million, eight hundred thirty-one thousand, five hundred nine".