71936641991 has 4 divisors (see below), whose sum is σ = 72334082184. Its totient is φ = 71539201800.

The previous prime is 71936641967. The next prime is 71936642023. The reversal of 71936641991 is 19914663917.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19914663917 = 43 ⋅463131719.

It is a cyclic number.

It is not a de Polignac number, because 71936641991 - 2²² = 71932447687 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 (71936641961) 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, 198719825 + ... + 198720186.

It is an arithmetic number, because the mean of its divisors is an integer number (18083520546).

Almost surely, 2^71936641991 is an apocalyptic number.

71936641991 is a deficient number, since it is larger than the sum of its proper divisors (397440193).

71936641991 is a wasteful number, since it uses less digits than its factorization.

71936641991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397440192.

The product of its digits is 2204496, while the sum is 56.

The spelling of 71936641991 in words is "seventy-one billion, nine hundred thirty-six million, six hundred forty-one thousand, nine hundred ninety-one".