91663775 has 12 divisors (see below), whose sum is σ = 129900912. Its totient is φ = 62855040.

The previous prime is 91663721. The next prime is 91663777. The reversal of 91663775 is 57736619.

It is not a de Polignac number, because 91663775 - 2¹⁶ = 91598239 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91663777) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 261722 + ... + 262071.

It is an arithmetic number, because the mean of its divisors is an integer number (10825076).

Almost surely, 2^91663775 is an apocalyptic number.

91663775 is a deficient number, since it is larger than the sum of its proper divisors (38237137).

91663775 is a wasteful number, since it uses less digits than its factorization.

91663775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 523810 (or 523805 counting only the distinct ones).

The product of its digits is 238140, while the sum is 44.

The square root of 91663775 is about 9574.1200640059. The cubic root of 91663775 is about 450.8851302740.

The spelling of 91663775 in words is "ninety-one million, six hundred sixty-three thousand, seven hundred seventy-five".