91082021 has 2 divisors, whose sum is σ = 91082022. Its totient is φ = 91082020.

The previous prime is 91082009. The next prime is 91082051. The reversal of 91082021 is 12028019.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 90820900 + 261121 = 9530^2 + 511^2 .

It is an emirp because it is prime and its reverse (12028019) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91082021 - 2¹⁸ = 90819877 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91082051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45541010 + 45541011.

It is an arithmetic number, because the mean of its divisors is an integer number (45541011).

Almost surely, 2^91082021 is an apocalyptic number.

It is an amenable number.

91082021 is a deficient number, since it is larger than the sum of its proper divisors (1).

91082021 is an equidigital number, since it uses as much as digits as its factorization.

91082021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 91082021 is about 9543.6901144159. The cubic root of 91082021 is about 449.9292415494.

The spelling of 91082021 in words is "ninety-one million, eighty-two thousand, twenty-one".