91555657 has 2 divisors, whose sum is σ = 91555658. Its totient is φ = 91555656.

The previous prime is 91555627. The next prime is 91555687. The reversal of 91555657 is 75655519.

It is a balanced prime because it is at equal distance from previous prime (91555627) and next prime (91555687).

It can be written as a sum of positive squares in only one way, i.e., 67584841 + 23970816 = 8221^2 + 4896^2 .

It is a cyclic number.

It is not a de Polignac number, because 91555657 - 2¹⁵ = 91522889 is a prime.

It is not a weakly prime, because it can be changed into another prime (91555627) 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, 45777828 + 45777829.

It is an arithmetic number, because the mean of its divisors is an integer number (45777829).

Almost surely, 2^91555657 is an apocalyptic number.

It is an amenable number.

91555657 is a deficient number, since it is larger than the sum of its proper divisors (1).

91555657 is an equidigital number, since it uses as much as digits as its factorization.

91555657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 236250, while the sum is 43.

The square root of 91555657 is about 9568.4720305804. The cubic root of 91555657 is about 450.7077865793.

The spelling of 91555657 in words is "ninety-one million, five hundred fifty-five thousand, six hundred fifty-seven".