91820087 has 2 divisors, whose sum is σ = 91820088. Its totient is φ = 91820086.

The previous prime is 91820081. The next prime is 91820123. The reversal of 91820087 is 78002819.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91820087 - 2⁸ = 91819831 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 (91820081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45910043 + 45910044.

It is an arithmetic number, because the mean of its divisors is an integer number (45910044).

Almost surely, 2^91820087 is an apocalyptic number.

91820087 is a deficient number, since it is larger than the sum of its proper divisors (1).

91820087 is an equidigital number, since it uses as much as digits as its factorization.

91820087 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8064, while the sum is 35.

The square root of 91820087 is about 9582.2798435445. The cubic root of 91820087 is about 451.1412791998.

The spelling of 91820087 in words is "ninety-one million, eight hundred twenty thousand, eighty-seven".