91820891 has 2 divisors, whose sum is σ = 91820892. Its totient is φ = 91820890.

The previous prime is 91820851. The next prime is 91820903. The reversal of 91820891 is 19802819.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 91820891 - 2¹⁴ = 91804507 is a prime.

It is not a weakly prime, because it can be changed into another prime (91820851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45910445 + 45910446.

It is an arithmetic number, because the mean of its divisors is an integer number (45910446).

Almost surely, 2^91820891 is an apocalyptic number.

91820891 is a deficient number, since it is larger than the sum of its proper divisors (1).

91820891 is an equidigital number, since it uses as much as digits as its factorization.

91820891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 91820891 is about 9582.3217958906. The cubic root of 91820891 is about 451.1425959652.

The spelling of 91820891 in words is "ninety-one million, eight hundred twenty thousand, eight hundred ninety-one".