91721485871 has 2 divisors, whose sum is σ = 91721485872. Its totient is φ = 91721485870.

The previous prime is 91721485861. The next prime is 91721485901. The reversal of 91721485871 is 17858412719.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91721485871 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91721485861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45860742935 + 45860742936.

It is an arithmetic number, because the mean of its divisors is an integer number (45860742936).

Almost surely, 2^91721485871 is an apocalyptic number.

91721485871 is a deficient number, since it is larger than the sum of its proper divisors (1).

91721485871 is an equidigital number, since it uses as much as digits as its factorization.

91721485871 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1128960, while the sum is 53.

The spelling of 91721485871 in words is "ninety-one billion, seven hundred twenty-one million, four hundred eighty-five thousand, eight hundred seventy-one".