71991129197 has 6 divisors (see below), whose sum is σ = 77954891562. Its totient is φ = 66453349872.

The previous prime is 71991129169. The next prime is 71991129251. The reversal of 71991129197 is 79192119917.

It can be written as a sum of positive squares in 3 ways, for example, as 348718276 + 71642410921 = 18674^2 + 267661^2 .

It is not a de Polignac number, because 71991129197 - 2²⁸ = 71722693741 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 (71991129167) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 212991338 + ... + 212991675.

It is an arithmetic number, because the mean of its divisors is an integer number (12992481927).

Almost surely, 2^71991129197 is an apocalyptic number.

It is an amenable number.

71991129197 is a deficient number, since it is larger than the sum of its proper divisors (5963762365).

71991129197 is a wasteful number, since it uses less digits than its factorization.

71991129197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425983039 (or 425983026 counting only the distinct ones).

The product of its digits is 642978, while the sum is 56.

The spelling of 71991129197 in words is "seventy-one billion, nine hundred ninety-one million, one hundred twenty-nine thousand, one hundred ninety-seven".