91897591 has 2 divisors, whose sum is σ = 91897592. Its totient is φ = 91897590.

The previous prime is 91897567. The next prime is 91897621. The reversal of 91897591 is 19579819.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91897591 - 2¹⁵ = 91864823 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 (91897511) 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, 45948795 + 45948796.

It is an arithmetic number, because the mean of its divisors is an integer number (45948796).

Almost surely, 2^91897591 is an apocalyptic number.

91897591 is a deficient number, since it is larger than the sum of its proper divisors (1).

91897591 is an equidigital number, since it uses as much as digits as its factorization.

91897591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 204120, while the sum is 49.

The square root of 91897591 is about 9586.3231220317. The cubic root of 91897591 is about 451.2681774330.

The spelling of 91897591 in words is "ninety-one million, eight hundred ninety-seven thousand, five hundred ninety-one".