71721710651 has 4 divisors (see below), whose sum is σ = 72704199912. Its totient is φ = 70739221392.

The previous prime is 71721710623. The next prime is 71721710657. The reversal of 71721710651 is 15601712717.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15601712717 = 103 ⋅151472939.

It is a cyclic number.

It is not a de Polignac number, because 71721710651 - 2¹⁸ = 71721448507 is a prime.

It is not an unprimeable number, because it can be changed into a prime (71721710657) 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, 491244521 + ... + 491244666.

It is an arithmetic number, because the mean of its divisors is an integer number (18176049978).

Almost surely, 2^71721710651 is an apocalyptic number.

71721710651 is a deficient number, since it is larger than the sum of its proper divisors (982489261).

71721710651 is an equidigital number, since it uses as much as digits as its factorization.

71721710651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 982489260.

The product of its (nonzero) digits is 20580, while the sum is 38.

The spelling of 71721710651 in words is "seventy-one billion, seven hundred twenty-one million, seven hundred ten thousand, six hundred fifty-one".