91691505 has 24 divisors (see below), whose sum is σ = 159255720. Its totient is φ = 48802560.

The previous prime is 91691491. The next prime is 91691507. The reversal of 91691505 is 50519619.

91691505 is a `hidden beast` number, since 91 + 69 + 1 + 505 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 11553201 + 80138304 = 3399^2 + 8952^2 .

It is not a de Polignac number, because 91691505 - 2⁷ = 91691377 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91691505.

It is not an unprimeable number, because it can be changed into a prime (91691507) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23815 + ... + 27395.

It is an arithmetic number, because the mean of its divisors is an integer number (6635655).

Almost surely, 2^91691505 is an apocalyptic number.

It is an amenable number.

91691505 is a deficient number, since it is larger than the sum of its proper divisors (67564215).

91691505 is a wasteful number, since it uses less digits than its factorization.

91691505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4161 (or 4158 counting only the distinct ones).

The product of its (nonzero) digits is 12150, while the sum is 36.

The square root of 91691505 is about 9575.5681293592. The cubic root of 91691505 is about 450.9305927412.

The spelling of 91691505 in words is "ninety-one million, six hundred ninety-one thousand, five hundred five".