91097785 has 4 divisors (see below), whose sum is σ = 109317348. Its totient is φ = 72878224.

The previous prime is 91097771. The next prime is 91097789. The reversal of 91097785 is 58779019.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11048976 + 80048809 = 3324^2 + 8947^2 .

It is a cyclic number.

It is not a de Polignac number, because 91097785 - 2⁵ = 91097753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91097789) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9109774 + ... + 9109783.

It is an arithmetic number, because the mean of its divisors is an integer number (27329337).

Almost surely, 2^91097785 is an apocalyptic number.

It is an amenable number.

91097785 is a deficient number, since it is larger than the sum of its proper divisors (18219563).

91097785 is a wasteful number, since it uses less digits than its factorization.

91097785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18219562.

The product of its (nonzero) digits is 158760, while the sum is 46.

The square root of 91097785 is about 9544.5159646784. The cubic root of 91097785 is about 449.9551971856.

The spelling of 91097785 in words is "ninety-one million, ninety-seven thousand, seven hundred eighty-five".