71991135 has 12 divisors (see below), whose sum is σ = 124784712. Its totient is φ = 38395248.

The previous prime is 71991131. The next prime is 71991167. The reversal of 71991135 is 53119917.

It is not a de Polignac number, because 71991135 - 2² = 71991131 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 71991135.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71991131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 799857 + ... + 799946.

It is an arithmetic number, because the mean of its divisors is an integer number (10398726).

Almost surely, 2^71991135 is an apocalyptic number.

71991135 is a deficient number, since it is larger than the sum of its proper divisors (52793577).

71991135 is a wasteful number, since it uses less digits than its factorization.

71991135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1599814 (or 1599811 counting only the distinct ones).

The product of its digits is 8505, while the sum is 36.

The square root of 71991135 is about 8484.7589830236. The cubic root of 71991135 is about 415.9996898882. Note that the first 3 decimals are identical.

The spelling of 71991135 in words is "seventy-one million, nine hundred ninety-one thousand, one hundred thirty-five".