91680206621 has 2 divisors, whose sum is σ = 91680206622. Its totient is φ = 91680206620.

The previous prime is 91680206599. The next prime is 91680206659. The reversal of 91680206621 is 12660208619.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65091316900 + 26588889721 = 255130^2 + 163061^2 .

It is a cyclic number.

It is not a de Polignac number, because 91680206621 - 2¹⁴ = 91680190237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91680206671) 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, 45840103310 + 45840103311.

It is an arithmetic number, because the mean of its divisors is an integer number (45840103311).

Almost surely, 2^91680206621 is an apocalyptic number.

It is an amenable number.

91680206621 is a deficient number, since it is larger than the sum of its proper divisors (1).

91680206621 is an equidigital number, since it uses as much as digits as its factorization.

91680206621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 41.

The spelling of 91680206621 in words is "ninety-one billion, six hundred eighty million, two hundred six thousand, six hundred twenty-one".