91061857 has 2 divisors, whose sum is σ = 91061858. Its totient is φ = 91061856.

The previous prime is 91061821. The next prime is 91061869. The reversal of 91061857 is 75816019.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79495056 + 11566801 = 8916^2 + 3401^2 .

It is an emirp because it is prime and its reverse (75816019) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91061857 - 2¹¹ = 91059809 is a prime.

It is not a weakly prime, because it can be changed into another prime (91061657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45530928 + 45530929.

It is an arithmetic number, because the mean of its divisors is an integer number (45530929).

Almost surely, 2^91061857 is an apocalyptic number.

It is an amenable number.

91061857 is a deficient number, since it is larger than the sum of its proper divisors (1).

91061857 is an equidigital number, since it uses as much as digits as its factorization.

91061857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15120, while the sum is 37.

The square root of 91061857 is about 9542.6336511468. The cubic root of 91061857 is about 449.8960368887.

The spelling of 91061857 in words is "ninety-one million, sixty-one thousand, eight hundred fifty-seven".