91778393 has 16 divisors (see below), whose sum is σ = 112218624. Its totient is φ = 73267200.

The previous prime is 91778387. The next prime is 91778399. The reversal of 91778393 is 39387719.

It is an interprime number because it is at equal distance from previous prime (91778387) and next prime (91778399).

It is a cyclic number.

It is not a de Polignac number, because 91778393 - 2¹⁶ = 91712857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91778399) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7568 + ... + 15518.

It is an arithmetic number, because the mean of its divisors is an integer number (7013664).

Almost surely, 2^91778393 is an apocalyptic number.

It is an amenable number.

91778393 is a deficient number, since it is larger than the sum of its proper divisors (20440231).

91778393 is a wasteful number, since it uses less digits than its factorization.

91778393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8072.

The product of its digits is 285768, while the sum is 47.

The square root of 91778393 is about 9580.1040182244. The cubic root of 91778393 is about 451.0729835689.

The spelling of 91778393 in words is "ninety-one million, seven hundred seventy-eight thousand, three hundred ninety-three".