91721485901 has 2 divisors, whose sum is σ = 91721485902. Its totient is φ = 91721485900.

The previous prime is 91721485871. The next prime is 91721485927. The reversal of 91721485901 is 10958412719.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69326363401 + 22395122500 = 263299^2 + 149650^2 .

It is a cyclic number.

It is not a de Polignac number, because 91721485901 - 2¹⁸ = 91721223757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91721485931) 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 as a sum of consecutive naturals, namely, 45860742950 + 45860742951.

It is an arithmetic number, because the mean of its divisors is an integer number (45860742951).

Almost surely, 2^91721485901 is an apocalyptic number.

It is an amenable number.

91721485901 is a deficient number, since it is larger than the sum of its proper divisors (1).

91721485901 is an equidigital number, since it uses as much as digits as its factorization.

91721485901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 181440, while the sum is 47.

The spelling of 91721485901 in words is "ninety-one billion, seven hundred twenty-one million, four hundred eighty-five thousand, nine hundred one".