91785057 has 32 divisors (see below), whose sum is σ = 159489792. Its totient is φ = 45563904.

The previous prime is 91785011. The next prime is 91785097. The reversal of 91785057 is 75058719.

It is not a de Polignac number, because 91785057 - 2⁶ = 91784993 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91785097) 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 in 31 ways as a sum of consecutive naturals, for example, 5248 + ... + 14529.

It is an arithmetic number, because the mean of its divisors is an integer number (4984056).

Almost surely, 2^91785057 is an apocalyptic number.

It is an amenable number.

91785057 is a deficient number, since it is larger than the sum of its proper divisors (67704735).

91785057 is a wasteful number, since it uses less digits than its factorization.

91785057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19817.

The product of its (nonzero) digits is 88200, while the sum is 42.

The square root of 91785057 is about 9580.4518160680. The cubic root of 91785057 is about 451.0839007268.

The spelling of 91785057 in words is "ninety-one million, seven hundred eighty-five thousand, fifty-seven".