91012591 has 2 divisors, whose sum is σ = 91012592. Its totient is φ = 91012590.

The previous prime is 91012583. The next prime is 91012601. The reversal of 91012591 is 19521019.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91012591 - 2³ = 91012583 is a prime.

It is equal to p_5272345 and since 91012591 and 5272345 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91012511) 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, 45506295 + 45506296.

It is an arithmetic number, because the mean of its divisors is an integer number (45506296).

Almost surely, 2^91012591 is an apocalyptic number.

91012591 is a deficient number, since it is larger than the sum of its proper divisors (1).

91012591 is an equidigital number, since it uses as much as digits as its factorization.

91012591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 810, while the sum is 28.

The square root of 91012591 is about 9540.0519390620. The cubic root of 91012591 is about 449.8148884722.

The spelling of 91012591 in words is "ninety-one million, twelve thousand, five hundred ninety-one".