91557899 has 2 divisors, whose sum is σ = 91557900. Its totient is φ = 91557898.

The previous prime is 91557887. The next prime is 91558007. The reversal of 91557899 is 99875519.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91557899 - 2⁴ = 91557883 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91557899.

It is not a weakly prime, because it can be changed into another prime (91557839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45778949 + 45778950.

It is an arithmetic number, because the mean of its divisors is an integer number (45778950).

Almost surely, 2^91557899 is an apocalyptic number.

91557899 is a deficient number, since it is larger than the sum of its proper divisors (1).

91557899 is an equidigital number, since it uses as much as digits as its factorization.

91557899 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1020600, while the sum is 53.

The square root of 91557899 is about 9568.5891854547. The cubic root of 91557899 is about 450.7114655022.

The spelling of 91557899 in words is "ninety-one million, five hundred fifty-seven thousand, eight hundred ninety-nine".